replacer simon by sandbox
big technical remake of mailsender module
Merge commit '97763fcbf4ac9a6c5f898d30d3bd73388023b5c7'

# By Nicole Rauch
# Via Nicole Rauch (2) and Andreas Leidig (1)
* commit '97763fcbf4ac9a6c5f898d30d3bd73388023b5c7':
  activitiesGroupsColorsAPI renamed to activitiesAPI.
  Renamed activitiesAPI to activitiesCoreAPI.
  Added test for the newly extracted function.
  Simplified the passing of a function.
  Slightly beautified invitation markdown.
  Extracted the first function from index and moved into the new activitiesGroupsColorsAPI. Moved color and groupname calculation logic from jade file into activitiesGroupsColorsAPI.
  extracted validation method and reused it in members and activities.
  Inlined "sinon" to prevent from accidental use.
  Added checks for endDate and endTime.
  Added some tests to activities/submit and refactored it the same way as members/submit.
small fixes after merge
button in invitation now looks bootstrappy
Merge branch 'master' of github.com:softwerkskammer/Agora

# By Nicole Rauch
# Via Nicole Rauch
* 'master' of github.com:softwerkskammer/Agora:
  Fixing the creation of new activities
fixed width is no good here
mini refactoring
Merge branch 'master' of github.com:softwerkskammer/Agora

# By Nicole Rauch
# Via Nicole Rauch
* 'master' of github.com:softwerkskammer/Agora:
  Also fixing saving of members.
Merge pull request #440 from leider/master

technical remake of mailsender module