[HOpenGL] light sources.

[Sven Panne]

FYI: The problem has been solved: When one uses lighting, one has to
specify normals, too. Otherwise the same normal (default: Vector3 0 0 1)
is used for all vertices/surfaces, yielding strange looking results.

Two hints: GLUT's renderObject can render some useful basic geometric
objects with correct normals, and GLUT's addTimerCallback is quite
handy for simple animation.

Cheers,
    S.