BUG: Fix to_datetime to properly deal with tz offsets #3944

Currently for certain formats of datetime strings, the tz offset will
just be ignored.
CLN: test_timeseries_legacy, specialize assert_

GH6175: replacing "assert_" with specialized form assertEqual. WIP: have not adjusted any instances of assert_( (... == ...).all() )
CLN: test_timeseries, specialize assert_

GH6175: replacing "assert_" with specialized form assertEqual. WIP: have not adjusted any instances of assert_( (... == ...).all() )
DOC: add links to other pages to contributing.rst
Merge pull request #6227 from y-p/PR_travis3

BLD: fix travis speedup
TST: add tests for algos.factorize (GH6212)
Merge pull request #6231 from jreback/test_factorize

TST: add tests for algos.factorize (GH6212)
Merge pull request #6207 from jorisvandenbossche/doc-contributing-update

DOC: add links to other pages to contributing.rst
BLD: more @network message skipping
BLD: fix travis caching on py3
BLD/DOC: add doc building to travis job. Basically for free
Merge pull request #6233 from y-p/PR_travis_docs

BLD: Build and publish docs (sans API) as part of Travis jobs
BLD: various test_perf fixes
Merge pull request #6235 from y-p/PR_tp

BLD: various test_perf fixes
RLS: set released to True. v0.13.1
RLS: kick off new release cycle
CLN: eliminate doc rst warning
COMPAT: pytables encoding reference invalid in python3.3
BUG: Fix ImportError on Python 3.4b2 and 3.4b3

See http://bugs.python.org/issue20166
Merge pull request #6241 from cgohlke/patch-1

BUG: Fix ImportError on Python 3.4b2 and 3.4b3