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.
GL_CULL_FACE is effectively always disabled, except for quad strip
rendering, and keeping GL_CULL_FACE disabled there does not seem
to cause any visual artifacts.
Instead, it enhances skeletal animation possibilities
(e.g. flipping bone strips over without it disappearing)
