Added properly functioning case insensitive match without regex

pandas.core.strings.str_contains should now match case insensitivity properly if given regex=False and case=False.  Also added test cases for case insensitive pandas.core.strings.str_contains with and without regex.
Documentation for str_contains bug in changelog
Redesigned pandas.io.gbq to remove bq.py as a dependency for everything except unit testing. Minor API changes were also introduced.
Squashed commit of the following:

commit 5e9e0fa29d727953583a116638a9d0db81f9ed21
Author: Michael Mueller <michaeldmueller7@gmail.com>
Date:   Thu Jun 26 19:53:35 2014 -0400

    Fixed issue with empty lines

commit 57b54918b251ab77f000b575d77bcce3affcb27a
Author: Michael Mueller <michaeldmueller7@gmail.com>
Date:   Thu Jun 26 16:31:27 2014 -0400

    Added reference to new functionality in docs

commit a2371638691584416439d3c6a4dd2ef1829dcbe3
Author: Michael Mueller <michaeldmueller7@gmail.com>
Date:   Thu Jun 26 16:26:06 2014 -0400

    Implemented functionality to ignore comment lines, wrote a test
BUG/TST: fix tests for groupby nth on Series (GH7559)
ENH: look for index columns in row after header
API: DatetimeIndex and PeriodIndex have same representation
Merge pull request #7602 from sinhrks/periodrepr

API: DatetimeIndex and PeriodIndex have same representation
Removing Python2.6 CI dependencies to test import failures
Fix typo in documentation

Signed-off-by: Julien Danjou <julien@danjou.info>
Merge pull request #7613 from jd/master

Fix typo in documentation
BUG: GroupBy.size created by TimeGrouper raises AttributeError
Merge pull request #7580 from jreback/groupby_nth

BUG/TST: fix tests for groupby nth on Series (GH7559)
Merge pull request #7600 from sinhrks/bingrouper

BUG: GroupBy.size created by TimeGrouper raises AttributeError
BUG: Timestamp.__new__ doesnt preserve nanosecond
Merge pull request #7610 from sinhrks/nanots

BUG: Timestamp.__new__ doesnt preserve nanosecond
BUG: Bug in to_timedelta that accepted invalid units and misinterpreted m/h (GH7611, GH6423)
Merge pull request #7616 from jreback/td

BUG: Bug in to_timedelta that accepted invalid units and misinterpreted m/h (GH7611, GH6423)
COMPAT: make numpy NaT comparison use a view to avoid implicit conversions
Merge pull request #7617 from jreback/nat2

COMPAT: make numpy NaT comparison use a view to avoid implicit conversions