[Gzz] OrthoCoordsys???

[Tuomas Lukka]

I now have made the OpenGL client boot but making it look
right is difficult: the new class OrthoCoordsys, which
is undocumented (neither the overall design nor javadocs)
is on the vob path and used by the VobVanishingClient indirectly. 

Benja: could you figure out what's the quickest way to implement
the similar stuff for OpenGL or alternatively, get rid of it?
I'll do the implementation once you document and explain.
Note that the resulting code needs to be FAST: if it isn't fast enough,
we need to scrap this approach.

        Tuomas