Update pyfaust according to what the previous commit (78e526cd) did for...

Update pyfaust according to what the previous commit (78e526cd) did for matfaust and add function FactParams.is_mat_consistent().

78e526cd also added the function to matfaust.
Its role is to verify that the size of the matrix to factorize is consistent with the defined constraints in the FactParams (or child) instances.