Merge pull request #2594 from cowlicks/deprecation-warings

TST: sparse: Remove tests with deprecated dtype casts
DOC: linalg: add fractional_matrix_power to docs
Merge pull request #2577 from argriffing/logm-update

ENH: linalg: better logm, sqrtm, add fractional matrix powers, add references and tests

This PR adds a couple of Pade approximations of matrix functions, using inverse
scaling and squaring. The implementations for logm and sqrtm are replaced, and
a new fractional_matrix_power function is added.

These are implemented from the reference publications listed in the docstrings.
One of the example matrices in one of the publications causes problems for the
current logm, and the new logm can handle it better; this example has been
included as a test.
STY: docstring style; this is my first commit to branch fetched from another user's scipy fork so it might screw up
STY: change single-line test docstrings to comments
TST: assert -> assert_
MAINT: remove fortran spam in tests
ENH: Add inequality overrides to complex_ops.h.
ENH: Add inequality routines to compressed types in sparsetools.
ENH: Regenerated SWIG wrappers.
ENH: Add inequalities to base.py
ENH: Add inequalities to compressed.py, bsr.py.
TST: Add tests for inequalities.
TST: Test for sparse inequalities with scalars on LHS.
STY: Changed idiom for filling matrices as suggested by pv.
Merge pull request #2586 from cowlicks/inequalities-override

ENH: sparse: implement inequality ops for sparse matrices
ENH: new bool_ops.h
STY: Homogenized spacings.
TST: Added bool rollover test.
ENH: Added macro to check at compile time that np_bool_wrapper is the correct size.