Switches now have an sell-by-date

The idea of an automated expiry date has worked well for our AB testing. It forces people
to think how long a feature should last in production, rather than the indefinate default.

If a feature has expired two things happen.

i. The feature is disabled.
ii. The tests will break, at which point someone should remove it or seek justification as to why it should live on.

The sell-by-date is optional at the moment (it default to 'the future'), but we'll make it permanent once the concept is understood by everyone.
Merge branch 'master' of https://github.com/guardian/frontend into sell_by_date

Conflicts:
	common/app/conf/switches.scala
Omit redundant group properties
Formatting
Merge branch 'master' of https://github.com/guardian/frontend into sell_by_date
Add features expiring within 7 days to the radiator
rename AlwaysOnSwitch -> NeverExpiresSwitch
Update guss layout component
Cross browser bug fixes
All features now mandate an expiry date
The future is 2100
Switchboard displays expiry date
Merge pull request #2711 from guardian/sell_by_date

Feature switches now have an sell-by-date
Added Omniture verification account

Added a second Omniture account (behind) a switch that runs on a really simple mechanism that we can use to verifiy the main (more-complex) account is working.
Merge pull request #2732 from guardian/facia-tool-no-default-group

Facia tool: Omit redundant group properties
Merge pull request #2733 from guardian/news-container-design-tweaks

News container design tweaks [cross-browser bug fixes]
Merge pull request #2737 from guardian/analytics-verification

Added Omniture verification account
Fixed test to reflect new Omniture URL
Merge branch 'master' of github.com:guardian/frontend into no-follow

Conflicts:
	common/app/conf/switches.scala
Merge branch 'master' of github.com:guardian/frontend into no-follow

Conflicts:
	common/app/conf/switches.scala