Merge branch 'master' into coreGLMac

Conflicts:
	glsl/IECoreGL/PointsPrimitive.h
	glsl/IECoreGL/VertexShader.h
	include/IECoreGL/GLUT.h
	include/IECoreGL/Lights.h
	include/IECoreMaya/DrawableHolderUI.h
	src/IECoreGL/PointsPrimitive.cpp