Blender Git Loki

Little design study for new API to replace various pbvh/sculpt
iterators (uncomment PROXY_ADVANCED in BKE_pbvh to enable):
+ Same idea as existing pbvh proxies.
+ Based on "struct of arrays" approach.
+ New ProxyVeryArray structure holds all the coordinates,
normals, indices, neighbor references, color, mask, etc
data--basically everything in PBVHVertIter and SculptNeightborIter.
+ Only the desired data is stored. Client code can pass a mask
stating which data layers it wants; e.g. normals, coordiantes, etc.

There's a lot of advantages to this approach: simpler and more
maintainable code, possibility of SSE/opencl/cuda vectorization down
the line, etc.

More importantly for this branch, it should be a great profiling tool.
No more trying to figure out which bit of API cruft is causing the CPU
cache to go haywire. I can eliminate a lot of performance bugs and
concentrate on the ones related to DynTopo.