Blender Git Loki

Optimization for particle baking to caches, skip evaluation of pathcache
when not needed.

The pathcache data is only required in the first frame to construct the
child strand shapes. For subsequent frames the children are calculated
using the initial shape and parent deformation, so particles don't need
to recalculate all the time.

This gives a significant performance increase of the baking process when
using a lot of complicated child hairs.