Ensure we do not render anything if GL is not available

Added more safeguards to ensure no rendering takes place if OpenGL
2.0 or later is not available, added some additional API to enable
the application to verify OpenGL.

Change-Id: I7f548789e8adaed2e9e63ad07c5ac7c70eb7af03
Merge topic 'invalid-context' into master

580ae9e5 Ensure we do not render anything if GL is not available