MAINT: fix hamming distance regression for exotic arrays, with unit test
TST: more changes like self.assertTrue(x == y, message) -> assert_equal(x, y)
Merge pull request #4319 from argriffing/revisit-hamming

MAINT: fix hamming distance regression for exotic arrays, with unit test
TST: assert_(x < y) -> assert_array_less(x, y)
TST: use numpy.testing in test_hierarchy.py
Merge pull request #4321 from argriffing/test-assertion-syntax-b

TST: more changes like self.assertTrue(x == y, message) -> assert_equal(x, y)
Merge pull request #4326 from argriffing/update-hierarchy-tests

TST: use numpy.testing in test_hierarchy.py
MAINT: stats: rename check_random_state test function
Merge pull request #4329 from ev-br/check_random_state

MAINT: stats: rename check_random_state test function
MAINT: some fixes for stats.wishart added in gh-4135.

Fix docstring formatting and use np.linalg.slogdet where indicated by TODOs.
TST: clean up stats._multivariate tests a bit.
DOC: add stats.wishart/invwishart to 0.16.0 release notes.

[ci skip]
BUG: stats.wishart: fix issue with using floats for size arg to numpy funcs.

This raises DeprecationWarning's with recent numpy; should clearly be ints.
BUG: stats.wishart: fix test failure due to two variants to calculate logdet(x)

These are subtly different:

    In [46]: 2 * np.sum(np.log(linalg.cholesky(scale, lower=True).diagonal()))
    ...      - np.log(np.linalg.det(scale))
    Out[46]: 8.8817841970012523e-16

Use of ``np.linalg.slogdet`` is preferred for readability/maintainability.
MAINT: wishart: revert to using Cholesky decomposition instead of slogdet.

This is faster, see discussion on gh-4313.  Using it everywhere fixes
the discrepancy between the normal and frozen distribution.
MAINT: document in stats.distributions when to stop special casing np.vectorize

Closes gh-4314.