MAINT: fix hamming distance regression for exotic arrays, with unit test
TST: a few changes like self.assertTrue(x == y, message) -> assert_equal(x, y)
TST: in test_signaltools, changes like self.assertTrue(x == y, message) -> assert_equal(x, y)
Merge pull request #4320 from argriffing/test-assertion-syntax

TST: a few changes like self.assertTrue(x == y, message) -> assert_equal(x, y)
Merge pull request #4322 from argriffing/test-assertion-syntax-c

TST: in test_signaltools, 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