[HOpenGL] GlxGears

[Sven Panne]

I wrote:
> [...] It runs with 7162 FPS now, which is only 0.03% slower than the C version! :-)

A small note: After a hint from SimonM, I've just made some minor performance tweaks
to the OpenGL package (making some constructor fields strict and letting GHC unbox
them automatically). The Haskell version is now *exactly* as fast as the C version.
:-)

Cheers,
    S.