add docs for a few functions; mark functions as static since they aren't used elsewhere
add docs for a few functions; mark functions as static since they aren't used elsewhere

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