added lighting, not working
attempting to use Angel example from chapter 5. Getting a GLXBadFBConfig error.
fixed error from previous commit. had to change glutInitContextVersion() arguments from 3, 2 to 2, 1. also had to change glsl versions from 1.5 to 1.3 in vshader and fshader.
moved to an example that renders the lights using the shaders instead of in the application.