Split grunt test tasks to make unit tests a separate task

So that the unit tests a.k.a the "fast" tests can be run separately from the full test suite, which is slow.
Update cheapseats version to include range parameters
Split travis build into 3 parts

One which runs the unit tests, and two which run (roughly) half of cheapseats each.
These can then be parallelised across multiple VMs so should sped up the process.

See http://docs.travis-ci.com/user/speeding-up-the-build/ for details.
Merge pull request #520 from alphagov/feature/optimise-travis

Feature/optimise travis
Fail travis build if any of the parallelised builds fail
Merge pull request #521 from alphagov/feature/optimise-travis

Fail travis build if any of the parallelised builds fail
Fix crashing bug in list module.

Extend list module to deal gracefully with empty datasets, and
show a nice "no data" message.
Fix non-overlapping ranges

Also tinker with the range a little to put more tests in the first batch. Because it contains more of the "high volume" dashboards (because they mostly start with a "d"), which are quicker to test.
Merge pull request #523 from alphagov/feature/optimise-travis

Fix non-overlapping ranges
Merge pull request #522 from alphagov/bugfix/crashing-bug-in-list-module

Fix crashing bug in list module.
The 24 hour filtering was the wrong way round

The problem reared its head when we stopped gathering realtime data for
around 8 hours before restarting. It was chopping the most recent data
off the front of the list of points.

I've switched the tests to use the correct collection so it exhibits the
same sorting and structure as the view will receive. I have also
reordered the data to reflect the order it comes back from backdrop.
Add new line for cleaner future changes
Tweak travis cheapseats build split to try and balance build times
Merge pull request #526 from alphagov/feature/optimise-travis

Tweak travis cheapseats build split to try and balance build times
Merge pull request #524 from alphagov/fix-realtime-filtering

The 24 hour filtering was the wrong way round
Show bars on 'bar chart with number' module.

This is so that we can show six quarters of data by default on the
high-volume bar charts.

Almost all of the high-volume services actually have data going
back six quarters (to Q4 2012) and the more we can show, the
more meaningful the graphs become.

Change font-size on the x-axis labels to 12px: this matches the
font size used for x-axis labels in journey graphs.
Update cheapseats pointer to include new bar chart tests