Fixes to allow module data update on go live. Fix to compulsory wildcard module bug.

* added module session value to module config options
* added a call to the moduledata modules() task in the go live function in programme model
Fixed bug with only getting one cluster per stage
removed the module session switch, which now works through a setting in the module config file
Made revalidation sooner.
Added more comments to moduledata task
Merge pull request #247 from unikent/bug/correct-cache-codes-on-api

Ensure Caching Policy Is Correct
Merge pull request #245 from unikent/feature/module-update-on-live

Feature/module update on live
Merge branch 'develop' into refactor/change-to-undergraduate

Conflicts:
	application/controllers/api.php