[HOpenGL] HOpenGL and the new library hierarchy

[Sven Panne]

Sorry for the long period of silence, but I'm currently slowly recovering
from a head crash (my hard disk's head, to be exact, not *mine* :-).

I'm going to re-implement HOpenGL based on the .spec files and the new FFI,
moving to the new library hierarchy on the way. So I'm seeking advice where
to put it exactly. My suggestion:

The GL/GLU modules reside into the subtrees

    Graphics.Drawing.OpenGL.GL
    Graphics.Drawing.OpenGL.GLU

with 2 modules of the same names, re-exporting the modules from the
subtrees. A module Graphics.Drawing.OpenGL re-exports those two modules
again.

The GLUT modules reside in Graphics.UI.GLUT, with a module of the same
name, re-exporting the modules below it plus Graphics.Drawing.OpenGL
(Graphics.UI.OpenGL.GLUT looks a little bit like overkill, IMHO).

I'm a little bit unhappy with "Drawing", "Rendering" would be more
appropriate, but I could live with that...

Comments/suggestions?

Cheers,
    S.