BUG: hashtable memory error causes test_factorize_nan crash
Merge branch 'hashtable' of https://github.com/mtkni/pandas into mtkni-hashtable

Conflicts:
	doc/source/release.rst
CLN: Deprecation of assertEquals

#7131: s/self.assertEquals(/self.assertEqual(
Merge pull request #7165 from bwignall/issue7131_assertEquals

CLN: Deprecation of assertEquals