BUG: sparse: fix issues with 0-size fancy indexing
MAINT: remove numpy.matrix usage from linalg.matfuncs.py code and enable expm of more array_likes
DOC: clarify matrix vs array in mmio docstrings

mmio docstrings and an error message seemed to imply use of np.matrix,
which is not the case.
BUG: fix behavior of write_values() with empty string in scipy.io.netcdf

fixes #1592
Merge pull request #3310 from matthew-brett/clarify-mmio-matrices

DOC: clarify matrix vs array in mmio docstrings
MAINT: remove np.matrix from logm and matrix power
MAINT: remove np.matrix from sqrtm
DEP: deprecate scipy.linalg.special_matrices.all_mat
ENH: sparse: add maximum and minimum binops to sparsetools
ENH: sparse: implement spmatrix.maximum and spmatrix.minimum
GEN: regenerate sparsetools
Merge pull request #3305 from jnothman/test_has_sorted_indices

BUG: sparse: ensure correct operation of has_sorted_indices

Fix errors in use of hasattr/getattr/et al. with mangled double-underscore
attribute names, by switching to unmangled names.
Merge pull request #3298 from pv/sparse-fix2

BUG: sparse: fix issues with 0-size fancy indexing
Merge pull request #3313 from andreas-h/gh1592

BUG: io/netcdf: fix behavior of write_values() with empty string in scipy.io.netcdf
Merge pull request #3296 from pv/sparse-minmax

ENH: sparse: implement maximum() and minimum() binops
Merge pull request #3315 from argriffing/remove-more-numpy-matrix

MAINT: linalg: remove more usage of numpy matrix
Merge pull request #3308 from argriffing/remove-some-mats

MAINT: linalg: code cleanups in matfuncs

Remove numpy.matrix usage from linalg.matfuncs.py code and enable expm of more array_likes.
Also misc code cleanups.
ENH provide a short-circuit for CSR/CSC/BSR sum_duplicates
FIX implementation of has_canonical_format (was is_canonical)