DOC: fix conflicting ewma documentation
Merge pull request #4499 from Komnomnomnom/moments-doc-

DOC: fix conflicting ewma documentation
BLD: test_perf, bring back pickle-compare code clobbered in 244d56751
BLD: test_perf, revert s/save/to_pickle change, warn the unwary
Merge pull request #4644 from y-p/PR_test_perf_fixes

test_perf fixes, restore clobbered pickle compare cmdargs, restore back_compat
BUG: Test and fix for subclasses of CacheableOffset (GH4609)
PERF: optimize __getitem__ in DataFrame for columns lookup
Merge pull request #4639 from jreback/gi_perf

PERF: optimize __getitem__ in DataFrame for columns lookup
ENH: (GH4629) Support for using a DatetimeIndex/PeriodsIndex directly in a datelike calculation
     e.g. s-s.index
BUG: Boolean indexing on an empty series loses index names
DOC add fix status for 4235
DOC: revised 0.13 internal refactoring to add np.where
Merge pull request #4658 from hayd/rebase4236

Boolean indexing on an empty series loses index names (rebase of 4236)
Fix issue #4496: tslib.tz_convert(vals, tz1, tz2) may raise an IndexError exception.
Merge pull request #4497 from stenri/tslib_tz_convert_trans_pos_plus_1__bugfix

Fix issue #4496: tslib.tz_convert(vals, tz1, tz2) may raise an IndexErro...
BUG: GH4273, appending a 0-len table to HDFStore was raising
Merge pull request #4660 from jreback/hdf_empty

BUG: GH4273, appending a 0-len table to HDFStore was raising
BUG: fixes issue #4322

Adds support for the thousands character in csv parser for floats.

Updated docs to reflect bug fix.
TST: Removed double import in test io.tests.parser_tests.
ENH: avoid branch in thousands check. Thanks to @cancan101