Blender Git Loki

Cycles: Speedup of Spatial BVH split code

Avoid memmove() happening on every insert of duplicated node to the references
list. Temporary pre-allocated vector is used for new references which is then
being inserted into actual array in one go later.

Gives around 4x speedup building spatially split BVH for the grass field in the
cassette player shot from Gooseberry.