GL_EXT_draw_buffers2
http://developer.download.nvidia.com/opengl/specs/GL_EXT_draw_buffers2.txt
	void glColorMaskIndexedEXT (GLuint index, GLboolean r, GLboolean g, GLboolean b, GLboolean a)
	void glGetBooleanIndexedvEXT (GLenum target, GLuint index, GLboolean *data)
	void glGetIntegerIndexedvEXT (GLenum target, GLuint index, GLint *data)
	void glEnableIndexedEXT (GLenum target, GLuint index)
	void glDisableIndexedEXT (GLenum target, GLuint index)
	GLboolean glIsEnabledIndexedEXT (GLenum target, GLuint index)