This untangles some of the gigantic kitchen sink headers
in an attempt to split things into smaller files.
Also don't include gl.h, glext.h, windows.h,
and other such nonsense *everywhere*.
Lots of cleanups on the way too. More dead/unused code removal.
Remove incrFlag(), decrFlag() Lua functions.
Started working on a tiny input/ActionMapper refactor,
then everything fell apart and i ended up doing this.
I'm sorry.
Pretty much untested because input mapping is broken right now,
will fix that next.