Removed unnecessary IRIS wrapper to rotate
Fix IRIS rotation test
Changed seconds calculation for timedelta.total_seconds()

Conflicts:
	sunpy/physics/transforms/differential_rotation.py
Removed the fixtures for 2.6 as they are not tested anymore
Removed an old work around to get test raised errors for 2.6
Add gitter notifications to Travis
Merge remote-tracking branch 'upstream/master' into iris
All old formating syntax (eg: "%s" % (var) ) has been changed to the
newer method: (eg: "{0}".format(var) ).  Also, some changes have been
done in some time formatings.
added astropy to the requirements
Merge pull request #1197 from dpshelio/req

added astropy to the requirements.txt
Changelog entry for removing redundant IRIS map-rotation method
Merge pull request #1189 from ayshih/iris

[Review]: Removed unnecessary IRIS wrapper to `Map.rotate()`
Merge pull request #1073 from dpshelio/TimeCalc_diffrot

[Review]: Removed all 2.6 heritage
First attempt at using astropy_helpers
Further setup.py work.
Start work on moving the docs over
Use https for astropy_helpers
Update astropy_helpers
Fix some doc weirdness with astropy_helpers.

Also make the mock import in conf.py only happen if it is needed.
Add astropy_helpers for relative import in conf.py

This assumes that astropy_helpers is in the root tree relative to the docs dir.
Changes to .travis.yml to try and make travis work