builder2 is now faster than reference implementation for hair geometry
first builder that works fast for triangles and hair without adjustments
cleanups
cleanups
copied bvh4hair_builder2 to bvh4_builder_hair
copied again traverser from bvh4hair to bvh4
made bvh4hair builders deterministic
made SAH calculation of BVH4 and BVH4Hair identical
favoring aligned nodes in bvh4 builder2