fix warnings in OpenGLTrueTypeFont
add upAxis option for Y or Z up
remove some warnings
Merge branch 'master' of https://github.com/bulletphysics/bullet3

Conflicts:
	btgui/OpenGLWindow/X11OpenGLWindow.cpp
remove OpenGL/glu.h from gl3 headers (warning), replace some OpenGL definitions ARB/non-ARB