https://bugzilla.gnome.org/show_bug.cgi?id=749846
Use them as such. They are also required for GL3 core profile support with glDrawElements on OS X.
- update for shaders - add alpha property - image placement properties shamelessly borrowed from gdkpixbufoverlay - image placement properties are GstController able - use GstGLMemory for the overlay image data - add support for gles2