ENH: Added != binop to BSR, CSC, and CSR files in sparsetools/ and
instantiate them.
ENH: Regenerated SWIG wrapper to accomodate changes with BSR, CSC, and
CSR.
ENH: Add == & != functionality for BSR, CSC, and CSR sparse matrices.
TST: Added tests for == & != operators for BSR, CSC, and CSR.
API: Change sparse matrix __bool__ & __nonzero__ to raise a ValueError
the same way NumPy does.
TST: Fixed a nonrelevant error that occured relating to a change in sparse.
TST: Tests for __bool__.
BUG: Change Spares' sum and mean methods to match Numpy's buhavior.
TST: Tests for the changed sum and mean methods.
Merge pull request #2549 from cowlicks/sum-mean-dtype

ENH: sparse: fix sparse matrix sum() and mean() accumulator data types

Behavior now matches Numpy.

Fixes gh-2534
Merge pull request #2561 from cowlicks/eq-ne-override

ENH: sparse: == and != functionality for CSC, CSR and BSR sparse matrices