Add stars to background in pong. Cherrypicked from JohnRThomas branch.
Add stars to background in pong. Cherrypicked from JohnRThomas branch.

runewake2/opengl-examples,JohnRThomas/opengl-examples,runewake2/opengl-examples,runewake2/opengl-examples,JohnRThomas/opengl-examples,runewake2/opengl-examples,JohnRThomas/opengl-examples,JohnRThomas/opengl-examples