It is now possible to define multiple overloads of the same function,
each with different parameters. This is extremely useful for
maintaining backwards compatibility in the face of the changes between
GL 4.3 and 4.4.
ISpecWriter implementations must now store explicit references to a
Settings object. Additionally, all code generation is now handled inside
the ISpecWriter implementation (it used to be scattered over all Type,
Parameter, etc classes resulting in unmaintainable spaghetti code.)
Improved ISpecWriter API by removing low-level implementation details.
Made Constant implement IComparable so it can be sorted before being written to output.
