Blender Git Loki

OpenSubdiv: Continue working on skipping CCG creation

Synchronize topology refiner directly from derived mesh and skip CCG geometry
creation in that case.

Gets rid of annoying derived mesh pointer in the CCGSubSurf structure, but needs
to add some information for coarse vertices positions.

Drawing code is totally removed now, no partitioning or material setting happens,
this code needs to be adopted to the case of missing CCG geometry. Maybe this
will require having some extra arrays in the CCGSubSurf structure, but generally
memory usage will still be much less than the previous integration.