CLN: remove util.counter, duplicates compat
BLD: travis, Install apt-get deps first
BLD: travis, future-proof pip args
Merge pull request #6017 from y-p/PR_cln_counter

Remove duplicated code and fix travis
ENH: improved inference of timedelta64[ns] and datetime64[ns] in the prescence NaT/None/NaN
     from object dtypes (GH5689)
CLN: refactor of timedelta routines to cython for inclusion in maybe_convert_objects
BUG: apply to a Series with a timedelta (GH5458)
ENH: improved timedelta inference for non-ns dtypes
BUG: timedelta64 merge/join issues (GH5695)
DOC: release note for timedelta changes

TST: skip tests on numpy < 1.7 as needed for timedeltas

BUG: fixup .abs for timedeltas
Merge pull request #5995 from jreback/timedelta_fixes

BUG/CLN: clarified timedelta inferences
DOC: make zipped HTML docs available GH1876
Merge pull request #6020 from y-p/PR_GH1876

DOC: make zipped HTML docs available GH1876
DOC: update mailing list
TST: remove test.py (accidently added)
DOC: fix parser docstring for 'quotechar', 'quoting' params; closes #5408
BLD: add zip_html command to docs make.py
Merge pull request #5408 from patricktokeeffe/fix-parser-docstring

DOC/BUG: fix details for 'quoting' parser parameter
BUG: scatter_plot ranges are unaligned among subframes GH5497
Merge pull request #5665 from acorbe/scatter_matrix_off_diagonal_aligned
BUG: Regression in Series with a multi-index via ix (GH6018)
CLN: Remove references to _SeriesIndexer (vestigial)
BUG/CLN: make xs a generic method