Added some tests to activities/submit and refactored it the same way as members/submit.
Added checks for endDate and endTime.
Inlined "sinon" to prevent from accidental use.
extracted validation method and reused it in members and activities.
Extracted the first function from index and moved into the new activitiesGroupsColorsAPI. Moved color and groupname calculation logic from jade file into activitiesGroupsColorsAPI.
Slightly beautified invitation markdown.
Simplified the passing of a function.
Added test for the newly extracted function.
Merge commit '804fd192d0e95aa0ae30ac27bfd563cc85b338c3'
Renamed activitiesAPI to activitiesCoreAPI.
activitiesGroupsColorsAPI renamed to activitiesAPI.
Merge pull request #439 from NicoleRauch/master

Started to separate UI logic from business logic in the activities module.