GL_MESA_ycbcr_texture
http://www.opengl.org/registry/specs/MESA/ycbcr_texture.txt
GL_MESA_ycbcr_texture
	GL_UNSIGNED_SHORT_8_8_MESA 0x85BA
	GL_UNSIGNED_SHORT_8_8_REV_MESA 0x85BB
	GL_YCBCR_MESA 0x8757
