FUNCTIONALIZED POLY(ARYLENE ETHER) COMPOSITION AND METHOD BACKGROUND OF THE INVENTION Curable compositions including reactively end-capped poly(arylene ether) resins and copolymerizable monomers have been described, for example, in U.S. Patent Nos. 5,071,922 to Nelissen et al., and 6,352,782 and 6,627,704 to Yeager et al., as well as U.S. Statutory Invention Registration No. H521 to Fan. The compositions described therein are useful in a wide variety of thermoset applications, but existing formulations lack the balance of properties that is desired for fabricating plastic-packaged electronic devices. In particular, there is a need for improved flow during molding without sacrificing post-cure physical properties such as stiffness and impact strength. BRIEF DESCRIPTION OF THE INVENTION A curable composition exhibiting an improved balance of mold flow and post-cure physical properties comprises a difunctionalized poly(arylene ether) having an intrinsic viscosity of about 0.05 to about 0.30 deciliter per gram at 25°C; and an olefinically unsaturated monomer. Other embodiments, including a method of preparing the curable composition, a cured composition, and an article comprising the cured composition, are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a transmission electron micrograph corresponding to Comparative Example 6. FIG. 2 is a transmission electron micrograph corresponding to Comparative Example 7. FIG. 3 is a transmission electron micrograph corresponding to Example 24. FIG. 4 is a transmission electron micrograph corresponding to Comparative Example 8. FIG. 5 is a transmission electron micrograph corresponding to Comparative Example 9. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors conducted extensive research to find a composition that would exhibit the desirable characteristics usually associated with poly(arylene ether)-based thennosets, such as high glass transition temperature, low coefficient of thermal expansion, and low dielectric constant, while exhibiting molding characteristics similar to those of the epoxy thermoset resins currently favored by the marketplace. Early research indicated that the composition cured rapidly, but that it exhibited less than desired flow during the early stages of curing. Extensive experimentation revealed that flow could be improved by reducing the intrinsic viscosity of the functionalized poly(arylene ether), but this change also reduced the stiffness and impact strength of the cured composition. Additional experiments showed, surprisingly, that improved flow can be achieved without sacrificing post-cure physical properties by employing a functionalized poly(arylene ether) of reduced intrinsic viscosity but increased polymerizable functionality. In particular, it has been found that a substantially improved property balance is obtained when the poly(arylene ether) contains two polymerizable groups (i.e., it is a "difunctionalized" poly(arylene ether)) and has an intrinsic viscosity of about 0.05 to about 0.30 deciliter per gram at 25°C. One embodiment is a curable composition comprising a difunctionalized poly(arylene ether) having an intrinsic viscosity of about 0.05 to about 0.30 deciliter per gram (dL/g) at 25°C, and an olefinically unsaturated monomer. Within the above stated range, the intrinsic viscosity of the difunctionalized poly(arylene ether) may be, more specifically, at least about 0.08 dL/g, even more specifically at least about 0.12 dL/g. Also within the above stated range, the intrinsic viscosity of the difunctionalized poly(arylene ether) may be, more specifically, up to about 0.25 dL/g, even more specifically up to about 0.20 dL/g. As used herein, a difunctionalized poly(arylene ether) is a poly(arylene ether) having a polymerizable carbon-carbon double bond at each end of the molecule. One method of preparing such molecules is to first prepare a poly(arylene ether) having a hydroxy group at each end of the molecule ("dihydroxy poly(arylene ether)"), then react the dihydroxy poly(arylene ether) with sufficient capping reagent to form polymerizable capping groups at each end of the molecule. Several approaches to dihydroxy poly(arylene ether) resins are known. First, monohydric and dihydric phenols may be copolymerized as described, for example, in U.S. Patent Nos. 4,521,584 and 4,677,185 to Heitz et al.; U.S. Patent No. 5,021,543 to Mayska et al.; U.S. Patent Application Publication No. 2003/0194562 Al to Ishii et al.; W. Risse et al., Makromolekulare Chemie (1985), volume 186, no. 9, pages 1835- 1853; and V. Percec et al., Polymer Bulletin (1990), vol. 24, no. 5, pages 493-500. Second, monohydroxy poly(arylene ether) resins may be reacted with a dihydric phenol in the presence of an oxidant as described, for example, in U.S. Patent Nos. 3,496,236 to Cooper et al., 5,880,221 to Liska et al., and 6,569,982 to Hwang et al. Third, monohydroxy poly(arylene ether) resins may be equilibrated with diphenoquinones as described, for example, in U.S. Patent Nos. 4,140,675 and 4,165,422 and 4,234,706 to White, 6,307,010 Bl to Braat et al., as well as European Patent Application No. 550,209 A2 to Aycock et al. Fourth, dihydric phenols and dihalophenol sulfones may be copolymerized in the presence of base as described, for example, in U.S. Patent Nos. 4,562,243 and 4,663,402 and 4,665,137 to Percec, and 5,965,663 to Hayase, as well as U.S. Statutory Invention Registration No. H521 to Fan. Fifth, a dicarbonyl adduct may be formed from a dihydroxyaromatic compound, the dicarbonyl adduct may be oxidized to the corresponding diester, and the diester may be hydrolyzed to provide the hydroxy-terminated arylene ether; this procedure is described, for example, in U.S. Patent No. 4,873,371 to Yeager et al. Sixth, monohydroxy poly(arylene ether) resins may be reacted with formaldehyde in the presence of an acid catalyst to form a dihydroxy poly(arylene ether) with an internal methylene group. This method is described, for example, in W. Risse et al., Makromolekulare Chemie (1985), volume 186, no. 9, pages 1835-1853. Seventh, a dihydric phenol may be copolymerized with a 4-halo-2,6-dialkylphenol in the presence of base. This method is described, for example, in W. Risse et al., Makromolekulare Chemie (1985), volume 186, no. 9, pages 1835-1853. The dihydroxy poly(arylene ether) to may be converted to a difunctionalized poly(arylene ether) using procedures known for adding polymerizable functional groups to poly(arylene ether) resins. Such procedures are sometimes referred to as "capping" the poly(arylene ether), and the reagents therefore are sometimes referred to as "capping reagents". For example, the hydroxy groups of the poly(arylene ether) may be reacted with an acid anhydride as described, for example, in U.S. Patent Nos. 3,375,228 to Holoch et al., 4,165,422 to White, 5,071,922 to Nelissen et al., 6,352,782 B2 to Yeager et al., and 6,384,176 Bl to Braat et al. As another example, the hydroxy groups of the poly(arylene ether) may be reacted with a free acid under conditions suitable for forming an ester linkage as described, for example, in U.S. Patent Application Publication No. 2003/0194562 Al to Ishii et al. As another example, the hydroxy groups of the poly(arylene ether) may be reacted with an acid halide as described, for example, in U.S. Patent Nos. 3,375,228 to Holoch et al. and 4,165,422 to White. As another example, the hydroxy groups of the poly(arylene ether) may be reacted with a ketene as described, for example, in U.S. Patent No. 3,375,228 to Holoch et al. As another example, the hydroxy groups of the poly(arylene ether) may be reacted with a haloalkyl group under basic conditions as described, for example, in U.S. Patent No. 4,562,243 to Percec and U.S. Statutory Invention Registration No. H521, to Fan. Although not all of the above references teach reactions with capping agents containing an ethylenically unsaturated group, their procedures can be adapted for this purpose. For example, the acid halide capping procedure of U.S. Patent Nos. 3,375,228 to Holoch et al. and 4,165,422 to White may be used with acrylic chloride or methacrylic chloride. In one embodiment, the reaction of the capping reagent with the dihydroxy poly(arylene ether) generates a (meth)acrylate capping group. (Meth)acrylic anhydride is a suitable capping reagent for this purpose. It will be understood that the prefix "(meth)acryl-" encompasses both "acryl-" and "methacryl- In one embodiment, the difunctionalized poly(arylene ether) has the structure (Figure Removed) wherein each occurrence of Ql is independently halogen, primary or secondary Ci-Ci2 alkyl, C2-Ci2 alkenyl, C2-Ci2 alkynyl, C|-Ci2 aminoalkyl, Ci-Ci2 hydroxyalkyl, phenyl, Ci-Ci2 haloalkyl, Ci-Cn hydrocarbyloxy, C2-Cu halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; each occurrence of Q2 is independently hydrogen, halogen, primary or secondary Ci-Ci2 alkyl, C2-Ci2 alkenyl, C2-Cj2 alkynyl, Ci-Ci2 aminoalkyl, Ci-Ci2 hydroxyalkyl, phenyl, Ci-Cn haloalkyl, Ci-C|2 hydrocarbyloxy, C2-Ci2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; each occurrence of x is independently 0 to about 100, with the proviso that the sum of each occurrence of x is at least three; each occurrence of R1 is Ci-Cu hydrocarbylene; each occurrence of m is 0 or 1; each occurrence of n is 0 or 1; each occurrence of R2-R4 is independently hydrogen or Ci-Cjg hydrocarbyl; and L has the structure (Figure Removed) wherein each occurrence of Rs and R6 is independently hydrogen, halogen, primary or secondary Ci-Ci2 alkyl, C2-Cu alkenyl, C2-Ci2 alkynyl, C|-C|2 aminoalkyl, Ci-C|2 hydroxyalkyl, phenyl, C|-C]2 haloalkyl, Ci-C12 hydrocarbyloxy, C2-Ci2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; z is 0 or 1; and Y has the structure wherein R7, R8, and R9 are each independently hydrogen, Ci-Ci2 hydrocarbyl, or the like. In the last substructure above, R8 and R9 may be disposed either cis or trans about the double bond. In one embodiment, the sum of each occurrence of x is at least 4. As used herein, "hydrocarbyl", whether used as a word or a prefix, refers to a residue that contains only carbon and hydrogen. The residue may be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated, or a combination thereof. However, when so stated, the hydrocarbyl residue, may contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. Thus, when specifically noted as containing such heteroatoms, the hydrocarbyl residue may also contain carbonyl groups, amino groups, hydroxyl groups, carboxylic acid groups, halogen atoms, or the like, or it may contain heteroatoms within the backbone of the hydrocarbyl residue. In another embodiment, the difunctionalized poly(arylene ether) has the structure (Figure Removed) wherein Q1 is methyl; each occurrence of Q2 is independently hydrogen or methyl; each occurrence of R2 is independently hydrogen or methyl; R3 and R4 are hydrogen; each occurrence of R5 and R6 is independently hydrogen, halogen, primary or secondary Cj-Ci2 alkyl, C2-Ci2 alkenyl, C2-C|2 alkynyl, Cj-Cu aminoalkyl, C hydroxyalkyl, phenyl, Ci-Ci2 haloalkyl, Ci-Ci2 hydrocarbyloxy, C halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; and each occurrence of x is 1 to about 100. In one embodiment, the sum of each occurrence of x is at least 4. In another embodiment, the difunctionalized poly(arylene ether) has the structure (Figure Removed) wherein Q1 is methyl; each occurrence of Q2 is independently hydrogen or methyl; each occurrence of R2 is independently hydrogen or methyl; R3 and R4 are hydrogen; each occurrence of R5 and R6 is independently hydrogen, halogen, primary or secondary Ci-Cu alkyl, C2-Ci2 alkenyl, C2-Ci2 alkynyl, Ct-C12 aminoalkyl, Ci-C|2 hydroxyalkyl, phenyl, Ci-Ci2 haloalkyl, Ci-C]2 hydrocarbyloxy, C2-Ci2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; R8 and R9 are independently hydrogen or Ci-C6 hydrocarbyl, or the like; and each occurrence of x is 1 to about 100. In another embodiment, the difunctionalized poly(arylene ether) has the structure (Figure Removed) wherein each occurrence of x is 1 to about 100, and z is 0 or 1. As discussed above, various synthetic methods may be used to prepare the difunctionalized poly(arylene ether). In one embodiment, the difunctionalized poly(arylene ether) is the product of a process comprising oxidatively polymerizing a monohydric phenol in the presence of a catalyst under conditions suitable to form a corresponding poly(arylene ether) and a corresponding diphenoquinone; separating the poly(arylene ether) and the diphenoquinone from the catalyst; equilibrating the poly(arylene ether) and the diphenoquinone to form a poly(arylene ether) having two terminal hydroxy groups; and reacting the poly(arylene ether) having two terminal hydroxy groups with a capping agent to form the difunctionalized poly(arylene ether). An illustrative example of a corresponding poly(arylene ether) is poly(2,6-dimethyl- 1,4-phenylene ether) prepared from oxidative polymerization of 2,6-dimethylphenol. An illustrative example of a corresponding diphenoquinone is S.S'.S.S'-tetramethyl-4,4'-diphenoquinone formed by oxidation of 2,6-dimethylphenol. In another embodiment, the difunctionalized poly(arylene ether) is the product of oxidative copolymerization of a monohydric phenol and a dihydric phenol. Suitable monohydric phenols generally have the structure (Figure Removed) wherein Q1 is halogen, primary or secondary Ci-Ci2 alkyl, C2-Ci2 alkenyl, alkynyl, Ci-C^ aminoalkyl, Ci-Ci2 hydroxyalkyl, phenyl, Ci-C^ haloalkyl, aminoalkyl, C|-Ci2 hydrocarbyloxy, C2-Ci2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; and Q2 is hydrogen, halogen, primary or secondary Ci-Ci2 alkyl, C2-Ci2 alkenyl, C2-C|2 alkynyl, Cj-Cn aminoalkyl, C\-C\i hydroxyalkyl, phenyl, Ci-Ci2 haloalkyl, Ci-C12 aminoalkyl, Ci-C|2 hydrocarbyloxy, C2-C]2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like. Many specific monohydric phenols are described, for example, in U.S. Patent No. 3,306,875 to Hay. In one embodiment, the monohydric phenol is 2,6-dimethylphenol, 2,3,6-trimethylphenol, or a mixture thereof. (Figure Removed) wherein each occurrence of R5 and R6 is independently hydrogen, halogen, primary or secondary Ci-Cn alkyl, C2-Ci2 alkenyl, C2-Ci2 alkynyl, Ci-Ci2 aminoalkyl, Ci-Ci2 hydroxyalkyl, phenyl, Ci-Ci2 haloalkyl, Ci-C)2 hydrocarbyloxy, C2-Ci2 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms, or the like; z is 0 or 1; and Y has the structure wherein R7, R8, and R9 are each independently hydrogen, Ci-Ci2 hydrocarbylj or the like. Specific suitable dihydric phenols include, for example, 3,3',5,5'-tetramethyl- 4,4'-biphenol, 1,1 -bis(4-hydroxyphenyl)methane, 1,1 -bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane ("bisphenol A" or "BPA"), 2,2-bis(4- hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, l,l-bis(4- hydroxyphenyl)propane, l,l-bis(4-hydroxyphenyl)-n-butane, bis(4- hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-1 -methylphenyl)propane, 1,1 -bis(4- hydroxy-t-butylphenyl)propane, bis(hydroxyaryl) alkanes such as 2,2-bis(4-hydroxy- 2,6-dimethylphenyl)propane ("tetramethyl bisphenol A" or "TMBPA") 2,2-bis(4- hydroxy-3 -bromophenyl)propane, 1,1 ^bis(4-hydroxyphenyl)cyclopentane, bis(hydroxyaryl)cycloalkanes such as l,l-bis(4-hydroxyphenyl)cyclohexane, and the like, and mixtures thereof. In one embodiment, the difunctionalized poly(arylene ether) is prepared by a method comprising isolation by devolatilization extrusion. Suitable procedures for devolatilization extrusion are described, for example, in U.S. Patent No. 6,384,176 Bl to Braat et al. In another embodiment, the difunctionalized poly(arylene ether) has less than 100 parts per million (ppm) of residual terminal -OH groups. Preparative procedures described in the working examples below are capable of producing difunctionalized poly(arylene ether) resin meeting this limitation. Preparative procedures described in the working examples below are capable of producing difunctionalized poly(arylene ether) resin meeting these limitations. In one embodiment, the difunctionalized poly(arylene ether) has a number average molecular weight of about 1,000 to about 10,000 atomic mass units (AMU), with the provisos that less than 10 weight percent of the difunctionalized poly(arylene ether) has a number average molecular weight less than about 500 AMU, and less than 25 weight percent of the difunctionalized poly(arylene ether) has a number average molecular weight less than about 1,000 AMU. In another embodiment, the difunctionalized poly(arylene ether) has a number average molecular weight of at least about 10,000 AMU, with the provisos that less than 2 weight percent of the difunctionalized poly(arylene ether) has a number average molecular weight less than about 500 AMU, and less than 5 weight percent, preferably less than 1 weight percent, of the difunctionalized poly(arylene ether) has a number average molecular weight less than about 1,000 AMU. In one embodiment, the difunctionalized poly(arylene ether) may have one or more of the following properties: a number average molecular weight less than 5,000 AMU, less than 1 weight percent of polymer having a molecular weight less than 500 AMU, less than 5 weight percent of polymer having a molecular weight greater than 30,000 AMU, at least 200 micromoles per gram of "vinyl" (i.e., carbon-carbon double bond) functionality, an acid number less than 1 milligrams KOH per gram, and a decomposition onset temperature greater than 450°C. Preparative procedures described in the working examples below are capable of producing difunctionalized poly(arylene ether) resin meeting these limitations. The curable composition comprises about 5 to about 90 parts by weight of the difunctionalized poly(arylene ether) per 100 parts by weight total of the difunctionalized poly(arylene ether) and the olefmically unsaturated monomer. Within this range, the amount of the difunctionalized poly(arylene ether) resin may specifically be at least about 10 parts by weight, more specifically at least about 15 parts by weight. Also within this range, the amount of the difunctionalized poly(arylene ether) resin may specifically be up to about 80 parts by weight, more specifically up to about 60 parts by weight, still more specifically up to about 50 parts by weight. In addition to the difunctionalized poly(arylene ether), the curable composition comprises an olefmically unsaturated monomer. The olefinically unsaturated monomer is herein defined as a polymerizable monomer comprising a carbon-carbon double bound. Suitable olefinically unsaturated monomers include, for example, alkenyl aromatic monomers, allylic monomers, acryloyl monomers, vinyl ethers, maleimides, and the like, and mixtures thereof. The alkenyl aromatic monomer may have the formula (Figure Removed) wherein each occurrence of R10 is independently hydrogen or Ci-Cig hydrocarbyl; each occurrence of R11 is independently halogen, Ci-Cu alkyl, Ci-C^ alkoxyl, or Ce-Cig aryl; q is 1 to 4; and r is 0 to 5. Unspecified positions on the aromatic ring are substituted with hydrogen atoms. Suitable alkenyl aromatic monomers include, for example, styrene, a-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, 1,3-divinylbenzene, 1,4-divinylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, styrenes having from 1 to 5 halogen substituents on the aromatic ring, and the like, and combinations thereof. In on embodiment, the alkenyl aromatic monomer is styrene. The olefinically unsaturated monomer may be an allylic monomer. An allylic monomer is an organic compound comprising at least one allyl (-CH2-CH=CH2) group. In one embodiment, the allylic monomer comprises at least two allyl groups. In another embodiment, the allylic monomer comprises at least three allyl groups. Suitable allylic monomers include, for example, diallyl phthalate, diallyl isophthalate, triallyl mellitate, triallyl mesate, triallyl benzenes, triallyl cyanurate, triallyl isocyanurate, mixtures thereof, partial polymerization products prepared therefrom, and the like, and mixtures thereof. The olefinically unsaturated monomer may be an acryloyl monomer. An acryloyl monomer is a compound comprising at least one acryloyl moiety having the structure (Figure Removed) wherein R12-R14 are each independently hydrogen, Ci-Ci2 hydrocarbyl, hydrocarbyloxycarbonyl, nitrile, formyl, carboxylic acid, imidate, thiocarboxylic acid, or the like. In one embodiment, the acryloyl monomer comprises at least two acryloyl moieties. In another embodiment, the acryloyl monomer comprises at least three acryloyl moieties. Suitable acryloyl monomers include, for example, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, isobornyl (meth)acrylate, methyl (meth)acrylate, methacryloxypropyl trimethoxysilane, ethoxylated (2) bisphenol A di(meth)acrylate, and the like, and mixtures thereof. It will be understood that the number following the ethoxylated term refers to the average number of ethoxy groups in the ethoxylate chain attached to each oxygen of bisphenol A. In one embodiment, the acryloyl monomer comprises at least two acryloyl moieties. In another embodiment, the acryloyl monomer comprises at least three acryloyl moieties. The olefinically unsaturated monomer may be a vinyl ether. Vinyl ethers are compounds comprising at least one vinyl ether (-O-CH=CH2) group. In one embodiment the vinyl ether contains at least two vinyl ether groups. In another embodiment, the vinyl ether contains at least three vinyl ether groups. Suitable vinyl ethers include, for example, 1,2-ethylene glycol divinyl ether, 1,3-propanediol divinyl ether, 1,4-butanediol divinyl ether, triethyleneglycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, ethyl vinyl ether, n-butyl vinyl ether, lauryl vinyl ether, 2-chloroethyl vinyl ether, and the like, and mixtures thereof. The olefinically unsaturated monomer may be a maleimide. A maleimide is a compound comprising at least one moiety having the structure (Figure Removed) Suitable maleimides include, for example, N-phenylmaleimide, 1,4-phenylene-bis- methylene-a,a'-bismaleimide, 2,2-bis(4-phenoxyphenyl)-N,N<-bismaleimide, N,N'- phenylene bismaleimide, N,N'-hexamethylene bismaleimide, N-N'-diphenyl methane bismaleimide, N,N'-oxy-di-p-phenylene bismaleimide, N,N'-4,4'-benzophenone bismaleimide, N,N'-p-diphenylsulfone bismaleimide, N,N'-(3,3'-dimethyl)methylene- di-p-phenylene bismaleimide, poly(phenylmethylene) polymaleimide, bis(4- phenoxyphenyl) sulfone-N,N'-bismaleimide, 1,4-bis(4-phenoxy)benzene-N,N'- bismaleimide, 1,3-bis(4-phenoxy)benzene-N,N'-bismaleimide, 1,3-bis(3- phenoxy)benzene-N,N'-bismaleimide, and the like, and mixtures thereof. The composition may generally comprise about 10 to about 95 parts by weight of the olefinically unsaturated monomer per 100 parts by weight total of the difunctionalized poly(arylene ether) and the olefinically unsaturated monomer. Within this range, the olefinically unsaturated monomer amount may specifically be at least about 20 parts by weight, more specifically at least about 30 parts by weight. Also within this range, the olefmically unsaturated monomer amount may specifically be up to about 80 parts per weight, more specifically up to about 60 parts by weight. As the curable composition is defined as comprising multiple components, it will be understood that each component is chemically distinct, particularly in the instance that a single chemical compound may satisfy the definition of more than one component. The curable composition may, optionally, further comprise a curing initiator. Curing initiators, also referred to as curing catalysts, are well known in the art and may be used to initiate the polymerization, curing, or crosslinking of numerous thermoplastics and thermosets including unsaturated polyester, vinyl ester and allylic thermosets. Non-limiting examples of curing initiators include those described in U.S. Patent Nos. 5,407,972 to Smith et al., and 5,218,030 to Katayose et al. The curing initiator may include any compound capable of producing free radicals at elevated temperatures. Such curing initiators may include both peroxy and non-peroxy based radical initiators. Examples of useful peroxy initiators include, for example, benzoyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, t-butyl benzene hydroperoxide, t- butyl peroctoate, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)-hex-3-yne, di-t-butylperoxide, t-butylcumyl peroxide, ct,a' -bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di(t-butylperoxy) isophthalate, t- butylperoxy benzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5- dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, trimethylsilylphenyltriphenylsilyl peroxide, and the like, and mixtures thereof. Suitable non-peroxy initiators include, for example, 2,3-dimethyl-2,3-diphenylbutane, 2,3-trimethylsilyloxy-2,3-diphenylbutane, and the like, and mixtures thereof. The curing initiator for the unsaturated portion of the thermoset may further include any compound capable of initiating anionic polymerization of the unsaturated components. Such anionic polymerization initiators include, for example, alkali metal amides, such as sodium amide (NaNHa) and lithium diethyl amide (LiN^Hj)*); alkali metal and ammonium salts of Ci-Cio alkoxides; alkali metal and ammonium hydroxides; alkali metal cyanides; organometallic compounds such as the alkyl lithium compound n-butyl lithium; Grignard reagents such as phenyl magnesium bromide; and the like; and combinations thereof. In one embodiment, the curing initiator may comprise t-butylperoxy benzoate or dicumyl peroxide. The curing initiator may promote curing at a temperature in a range of about 0°C to about 200°C. When present, the curing initiator may be used at about 0.1 to about 5 parts by weight per 100 parts by weight total of the difunctionalized poly(arylene ether) and the olefinically unsaturated monomer. Within this range, the curing initiator amount may specifically be at least about 0.5 part by weight, more specifically at least about 1 part by weight. Also within this range, the curing initiator amount may specifically be up to about 4 parts by weight, more specifically up to about 3 parts by weight. Alternatively, the curing initiator amount may be expressed in units of micromoles per gram of resin, where "resin" consists of the difunctionalized poly(arylene ether) and the olefinically unsaturated monomer. In this embodiment, the curing initiator amount is at least about 100 micromoles per gram of resin. The curable composition may, optionally, further comprise a curing inhibitor. Suitable curing inhibitors include, for example, diazoaminobenzene, phenylacetylene, sym-trinitrobenzene, p-benzoquinone, acetaldehyde, aniline condensates, N,N'-dibutyl-o-phenylenediamine, N-butyl-p-aminophenol, 2,4,6-triphenylphenoxyl, pyrogallol, catechol, hydroquinone, monoalkylhydroquinones, p-methoxyphenol, t-butylhydroquinone, Ci-Cs-alkyl-substituted catechols, dialkylhydroquinone, 2,4,6-dichloronitrophenol, halogen-ortho-nitrophenols, alkoxyhydroquinones, mono- and di- and polysulfides of phenols and catechols, thiols, oximes and hydrazones of quinone, phenothiazine, dialkylhydroxylamines, and the like, and combinations thereof. Suitable curing inhibitors further include uncapped poly(arylene ether)s (i.e., poly(arylene ether)s having free hydroxyl groups). In one embodiment, the curing inhibitor comprises benzoquinone, hydroquinone, 4-t-butylcatechol, or a mixture thereof. When the curing inhibitor is present, it may be used at about 0.005 to about 1 part by weight per 100 parts by weight total of the difunctionalized poly(arylene ether) and the olefinically unsaturated monomer. Within this range, the curing inhibitor amount may specifically be at least about 0.05 part by weight, more specifically at least about 0.1 part by weight. Also within this range, the curing inhibitor amount may specifically be up to about 0.5 part by weight, more specifically up to about 0.3 part by weight. In one embodiment, the curing inhibitor amount may be expressed in units of micromoles per gram of resin, where "resin" consists of the difunctionalized poly(arylene ether) and the olefinically unsaturated monomer. In this embodiment, the curing inhibitor amount may be at least about 50 micromoles per gram of resin. The composition may, optionally, further comprise an adhesion promoter to improve adhesion between the cured composition and metallic substrates, particularly leadframes used in semiconductor packages. Suitable adhesion promoters include metal (meth)acrylate salts, combinations of an aromatic epoxy compound and an aromatic amine, copolymers of a vinyl aromatic compound and an ct,|3-unsaturated cyclic anhydride, partially (meth)acrylated epoxy compounds, and the like, and mixtures thereof. Metal (meth)acrylate salts may have the structure (Figure Removed) wherein each occurrence of R15 is independently hydrogen or methyl, M is a metal from Groups 1-15 of the periodic table, and p is an integer from 1 to 6 corresponding to the valence of M. In one embodiment, M is a metal from Groups 1, 2, 12, or 13 of the periodic table. In one embodiment, M is zinc and p is 2. Combinations of an aromatic epoxy compound and an aromatic amine include those copolymers where the aromatic epoxy compound is a bisphenol-based epoxy resin (e.g., bisphenol A glycidyl ethers, bisphenol F glycidyl ethers, 4,4'-diphenol glycidyl ethers, 2,2',6,6'-tetramethyl-4,4'-diphenol glycidyl ethers), a novolak-type epoxy resin, or the like, or mixtures thereof; and the aromatic amine is a monocyclic aromatic amine (e.g., aniline, toluidine), a monocyclic aromatic diamine (e.g., diaminobenzene, xylylenediamine), a monocyclic aromatic amino alcohol (e.g., aminophenols), a polycyclic aromatic diamine (e.g., diaminodiphenylmethanes, tetramethyldiaminodiphenylmethanes, and diaminodiphenylsulfones), a polycyclic aromatic amine, or the like, or mixtures thereof. The aromatic epoxy compound and the aromatic amine may be used in a ratio such that the molar ratio of epoxy groups to amino hydrogen atoms is about 1:2 to about 2:1. When the adhesion promoter comprises a copolymer of a vinyl aromatic compound and an