editmesh texface drawing, reuse customdata offset rather then looking up each UV and vertex color, gives overall ~9.5% drawing speedup in my tests.
was also doing NULL checks on UV's which are never NULL in this case.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53701 954f8c5b-7b00-dc11-b283-0030488c597c