parallel_for can be forced to be sequential for debugging
added parallel_prefix_sum
optimized and simplified parallel_for_for
cleanups in parallel_for_for_prefix_sum
bugfix in parallel_for_for
Merge branch 'devel' of https://github.com/embree/embree into devel
using 12 byte alignment for vertices in verify
bugfix, vertex buffer alignment of 4 bytes supported now
bugfix in file extension check
Merge branch 'devel' of https://github.com/embree/embree into devel
updates new_features
improved compile time of bvh4_builder_fast