Collision against patches: do some major optimizations.

Collision against patches: do some major optimizations.
Keep an array of combined mins and maxs of every 32 consecutive triangles of the patch mesh.
Always collide against the mins/maxs in this array first before actually trying the triangles.
Improves collision performance a LOT, testcase.pk3 (a huge 31x31 patch mesh) becomes playable.
mod_q3bsp_collision_curves_stride value still needs optimizing, I think.

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@9065 d7cf8633-e32d-0410-b094-e92efae38249