SCR: test_perf can save results frame to pickle file, -d
TST: Test to_csv in more cases and faster
TST: add test for test in test_testing
BUG: check_less_precise in assert_almost_equal with val=float throws exception
DOC release notes add assert_frame_equal checks index and column names
Merge pull request #3172 from jreback/docs

DOC: minor edits in io.rst / cookbook.rst
Merge pull request #3174 from hayd/assert-frame-equal-doc

DOC release notes add assert_frame_equal checks index and column names
DOC: better error message on ndarray construction, GH3105

CLN: refactor to put all block manager creation calls into internals.py
     so to wrap with invalid constructions
TST: now py3 compatible