New extension loading code generator using OpenGL registry XMLs.
Merge branch 'master' of github.com:ubershader/GLSlayer

Conflicts:
	source/opengl/GLRenderContext_Windows.cpp
	source/opengl/extensions/glext_windows_funcs.h
	source/opengl/extensions/glext_windows_ptrs.h
	source/opengl/extensions/wglext_ptrs.h
	vs2012/GLSlayer/GLSlayer.vcxproj
	vs2012/GLSlayer/GLSlayer.vcxproj.filters