multithreaded op and fixed ssd validation issue.
Merge pull request #331 from valeriebernard/multithreadedSkinningOp

multithreaded op and fixed ssd validation issue.
Added boost::hash compatibility for MurmurHash.

This means we can use MurmurHash as the key in containers like boost::unordered_map.
Merge pull request #332 from johnhaddon/murmurHashHash

Added boost::hash compatibility for MurmurHash.