Blender Git Loki

Sculpt dyntopo: Removed triangle limit for PBVH_BMESH

* PBVH_BMESH now supports faces other then triangles;

* Dyntopo triangulates faces as it finds them.
- I looked into methods of preserving quads and failed to
find anything that worked well in practice; it actually
worked better to use topology rake to align triangles
into quads and then mark diagonal edges for later dissolving
then to try to preserve quads explicitly (I've not
implementated that here, that was research code).
- To avoid excessive cache-destroying loops over vertex-faces,
DynTopo flags which verts have non-triangle faces.

* PBVHTriBuf now builds edge buffers so we can avoid drawing
tesselation phantom edges.

* BMLog also now supports arbitrary faces. It still does not
support edges though.

TODO:

* Fix vcol cell shading mode
* Make sure indexed drawing works