merged q3msurface_t into msurface_t

merged q3msurface_t into msurface_t
renamed brushq1./brushq3. surface stuff to brush.
surface->texinfo->texture is now also copied into surface->texture for convenient access (and consistency with q3bsp)
the qc surface info extension has been made q3bsp friendly (however querying a surface's points won't give very sane results on q3bsp surfaces!)
a little cruft removal in some structures

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@5051 d7cf8633-e32d-0410-b094-e92efae38249