Increase multidimensional testing for sparsematrix module

[ajpotts]

Increase multidimensional testing for sparsematrix module

[ajpotts]

The sparsematrix module is nearly compliant: all N-D paths are either irrelevant or disabled.

The only missing piece is a unit test that asserts create_sparse_matrix raises ValueError if given a 2-D pdarray for rows/cols/vals.