AST: Moved GenStmnt/ArithEq.cpp statics into namespace.
IR: Added OpCode as a Code and size to replace size variants of codes.
Bytecode::MgC: Updated Call translation.
libGDCC: Updated assembly for new syntax.

Since everything needed updating, also cleaned up with the new optional offset and prefixed string syntax.
Bytecode::ZDACS: Updated Call translations for opsize.
Bytecode::ZDACS: Updated bitwise translations for opsize.
Bytecode::ZDACS: Updated Move_W translation for opsize.
Bytecode::ZDACS: More updates for opsize.

This should cover all of the true N-word codegen instructions. The remaining updates will most likely only support sizes already supported.
Also took the opportunity to clean up nearby code.
CC: Fixed Retn opsize usage.
Bytecode::ZDACS: Updated remaining instructions to use opsize.
libGDCC: Fixed bad Retn usage in assembly.
IR: Removed size variants of codes.