gropengl bug

[Taylor Richards]

Someone pointed out a problem where in the low detail setting the game
was extremely slow and used a ton of memory.  The problem was in
opengl_tcache_get_adjusted_texture_size() where tex_(w|h) would get set
to 131072.  This patch (few lines from grd3dtexture) fixes the problem. 
If there is something better that needs to be done I'm open to it,
otherwise I'll going to go ahead and commit this in the next few hours.


Taylor

-- 
Taylor Richards <mtrs at bellsouth.net>