Fixes to programme live field so it's used as a flag for whether a programme is live (2), unpublished (0), or live but has a newer version unpublished (1)
Merge branch 'develop' of https://github.com/unikent/programmes-plant into feature/programme-listing-ui-issue-91
Added display of a programme's editing status to the main listing

* displays 'editing' when a programme's live version isn't the newest
* displays 'published' when a programme's live version is the newest
* displays 'new' when no version has been published
* tests added
* js modified for data tables to allow for the extra column
Merge branch 'develop' of https://github.com/unikent/programmes-plant into feature/programme-listing-ui-issue-91
Merge branch 'develop' of https://github.com/unikent/programmes-plant into feature/programme-listing-ui-issue-91
Added functionality for revert to revision to the 'live' programme field.

* Revert to revision now sets the live field correctly.
* Added tests
* Added tooltip to programme listing status tags
Added language file entries for the traffic-light indicators and tooltips on the programme index page
Merge pull request #158 from unikent/feature/programme-listing-ui-issue-91

Feature/programme listing ui issue 91