Adresses #159 - Logout removes user specific data from cache.
Adresses #159 - Fixed a syntax error.
Adresses #159 - Implemented prefill cache for timetable / calendar.
Adresses #159 - Using Backbone.fetchCache.clearItem() instead of deleting items directly.
Adresses #159 - Added prefill spinner loading feedback on calendar / timetable.
Adresses #159 - Replaced backbone.fetch-cache with custom version.

The library will be switched back to the original version as soon as our customization is pulled into the repo.
Adresses #159 - Using prefillExpires in calendar / timetable.
Adresses #159 - Extracted cache defaults into utils.
Adresses #159 - Added caching for lectures.
Adresses #159 - Added caching for grades.
Adresses #159 - Added caching for news.
Adresses #159 - Added caching for events.
Adresses #159 - Added caching for rooms.
Merge branch '159-localStorage'