GL_ARB_draw_buffers_blend
http://www.opengl.org/registry/specs/ARB/draw_buffers_blend.txt
GL_ARB_draw_buffers_blend
	void glBlendEquationSeparateiARB (GLuint buf, GLenum modeRGB, GLenum modeAlpha)
	void glBlendEquationiARB (GLuint buf, GLenum mode)
	void glBlendFuncSeparateiARB (GLuint buf, GLenum srcRGB, GLenum dstRGB, GLenum srcAlpha, GLenum dstAlpha)
	void glBlendFunciARB (GLuint buf, GLenum src, GLenum dst)
