Mostly just cleanup and renaming of certain stuff (mostly in dependencies).
* Changed uw and sw to usize and ssize.
* Removed zpl_cast usage throughout dependencies
* No longer using GEN_DEF_INLINE & GEN_IMPL_INLINE
* header_start.hpp renamed to platform.hpp for depdendencies header.
Also upated the gencpp.refactor script with almost all relevant symbols.
gen.undef.macros.hpp also filled out
Ready to complete gencpp related todos left in implementation...