make compute_hash for matrices generic in the right way
Abstracted out the sparse matrix like operations from neuralClasses.h into a separate file, USCMatrix.h. Slight speed hit, but perhaps we could get a two-for-one speedup by optimizing uscmm_sparse_dense.
Changed functions that take Matrix as parameter to the recommended style (http://eigen.tuxfamily.org/dox/TopicFunctionTakingEigenTypes.html) to reduce copying. There was a speedup but not very much
multithreaded uscmm_sparse_dense for a pretty good speedup