MOLD STACK. A MOLDING SYSTEM INCORPORATING SAME AND A METHOD OF ALIGNING THE MOLD STACK TECHNICAL FIELD The present invention generally relates to, but is not limited to, molding systems, and more specifically the present invention relates to, but is not limited to, a mold stack, a molding system incorporating same and a method of aligning the mold stack. BACKGROUND OF THE INVENTION Molding is a process by virtue of which a molded article can be formed from molding material by using a molding system. Various molded articles can be formed by using the molding process, such as an injection molding process. One example of a molded article that can be formed, for example, from polyethylene terephthalate (PET) material is a preform that is capable of being subsequently blown into a beverage container, such as, a bottle and the like. A typical molding system includes an injection unit, a clamp assembly and a mold assembly. The injection unit can be of a reciprocating screw type or of a two-stage type. The clamp assembly includes inter alia a frame, a movable platen, a fixed platen and an actuator for moving the movable platen and to apply tonnage to the mold assembly arranged between the platens. The mold assembly includes inter alia a cold half and a hot half. The hot half is usually associated with one or more cavities (and, hence, also sometimes referred to by those of skill in the art as a "cavity half), while the cold half is usually associated with one or more cores (and, hence, also sometimes referred to by those of skill in the art as a "core half). The one or more cavities together with one or more cores define, in use, one or more molding cavities. The hot half can also be associated with a melt distribution system (also referred to sometimes by those of skill in the art as a "hot runner") for melt distribution. The mold assembly can be associated with a number of additional components, such as neck rings, neck ring slides, ejector structures, wear pads, etc. As an illustration, injection molding of PET material involves heating the PET material (ex. PET pellets, PEN powder, PLA, etc.) to a homogeneous molten state and injecting, under pressure, the so-melted PET material into the one or more molding cavities defined, at least in part, by the aforementioned one or more cavities and one or more cores mounted respectively on a cavity plate and a core plate of the mold assembly. The cavity plate and the core plate are urged together and are held together by clamp force, the clamp force being sufficient enough to keep the cavity and the core akces together against the pressure of the injected PET material. The molding cavity has a shape that substantially corresponds to a final cold-state shape of the molded article to be molded. The so-injected PET material is then cooled to a temperature sufficient to enable ejection of the so-formed molded article from the mold. When cooled, the molded article shrinks inside of the molding cavity and, as such, when the cavity and core plates are urged apart, the molded article tends to remain associated with the core. Accordingly, by urging the core plate away from the cavity plate, the molded article can be demolded, i.e. ejected from the core piece. Ejection structures are known to assist in removing the molded articles from the core halves. Examples of the ejection structures include stripper plates, ejector pins, etc. SUMMARY OF THE INVENTION According to a first broad aspect of the present invention, there is provided a mold stack. The mold stack comprises a first molding cavity defining component, a second molding cavity defining component and a third molding cavity defining component, with the second molding cavity defining component being located, in use, in-between the first molding cavity defining component and the third molding cavity defining component. At least one of the first molding cavity defining component and the third molding cavity defining component is associated with a respective compensator, the respective compensator configured to allow the at least one of the first molding cavity defining component and the third molding cavity defining component to align itself relative to the second molding cavity defining component. There is also provided a mold incorporating the mold stack and a molding system incorporating the mold. According to a second broad aspect of the present invention, there is provided a method of aligning a mold stack, the mold stack including a first molding cavity defining component, a second molding cavity defining component and a third molding cavity defining component, with the second molding cavity defining component being located, in use, in-between the first molding cavity defining component and the third molding cavity defining component; at least one of the first molding cavity defining component and the third molding cavity defining component being associated with a respective compensator. The method comprises positively locating the second molding cavity defining component; aligning the at least one of the first molding cavity defining component and the third molding cavity defining component relative to the second molding cavity defining component. According to a third broad aspect of the present invention, there is provided a mold stack. The mold stack comprises a first molding cavity defining component, a second molding cavity defining component and a third molding cavity defining component; one of the first molding cavity defining