Feature tests for licensing availability data
Add collection for querying licensingAvailabilityData

@gtrogers
@pbadenski
Add view for licensing uptime
Rename realtime -> uptime
Wire up for licensing uptime.

Feature tests wont work because we aren't using
a js client to drive them, looking into that next.
Update feature test to account for new <section>
Add BackdropStub for loading files for given parameters

Planning to use this to serve up json responses
from a test-only controller so that we can test the
javascript realistically without having to spin up
backdrop
Delete empty controller test
Route backdrop stub controller in dev and test envs
Return nil from stub if params can't be matched
Rename feature test
Use .nil? instead of unless
Add uptime for licensing + javascript feature tests.

- Adding poltergiest for testing javascript in feature tests
- Fixed licensing availability collection to use correct data format
- Added backdrop stub controller for feature testing javascript
- Glued it all together

@alexmuller
@gtrogers
Merge branch 'master' into availability-data-from-pingdom

Conflicts:
	app/assets/javascripts/licensing/controllers/overview.js
Increse default wait time for capybara
Merge pull request #102 from alphagov/availability-data-from-pingdom

Licensing uptime stat.