Blender Git Loki

CustomData layer for storing hair root locations as MSurfaceSamples.

This requires converting the old messy particle num/num_dmcache/fuv/foffset
data into the new mesh samples, which can potentially introduce floating
point errors and inaccuracies due to lack of face index mapping in the
new system. However, in any well-constructed particle system the hair
roots should be nearest to their num face, so mapping would be accurate
enough. If necessary face index data could be added to samples as a
legacy code hack, but probably it's best to eventually replace the
hair system as a whole anyway.