ENH support getting single element from CSR/CSC where duplicates are present
TST: sparse: accept Numpy dev versions in >= 1.9.0 version checks
TST: sparse: fix some issues in sparse non-canonical tests + mark new known failures
TST: sparse: fix dense-sparse in-place op tests

These tests previously assumed that ndarray.__imul__(sparse) would
correspond to elementwise product. This behavior in __numpy_ufunc__ was
changed in Numpy, so that "a *= b" corresponds to sparse.__rmul__
(similarly as "a = a*b").
TST: sparse: Py3 fix
Merge pull request #3269 from jnothman/get_single_duplicate

ENH: sparse: getting single element from CSR/CSC sparse matrix with duplicates
ENH: sparse: add maximum and minimum binops to sparsetools
ENH: sparse: implement spmatrix.maximum and spmatrix.minimum
GEN: regenerate sparsetools