Merge pull request #592 from NicoleRauch/master

Activities
removed timeFormat from full calendar configuration to hide it in the events' display
fetching query via npm now
   -> do an npm install
Changed Layout of Blogposts on group page
layouting tweaks in header
Merge pull request #593 from leider/master

Layout and rendering stuff
Simplified activitystore: upcoming and past activities are never queried relative to some date.
Bugfix #310: Currently ongoing activities are only listed as upcoming, not as past.