0030618: Modeling Algorithms, BOPTools_Parallel - avoid using map for thread-local...

0030618: Modeling Algorithms, BOPTools_Parallel - avoid using map for thread-local contexts without TBB

OSD_Parallel::ToUseOcctThreads() - new flag allowing to use OCCT threads implementation even when compiled with TBB (for testing).
Added new command dparallel for managing default Thread Pool.
OSD_Parallel::For() now avoid creation of universal iterator in simplest case.

BOPTools_Parallel - eliminated redundant typedefs/explicit instantiations of templates.
Added functor using array of per-thread context instead of a map.