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.
Added newline.
Merge pull request #594 from NicoleRauch/master

Bugfix #310
refactored display of nicknames to use a mixin and added the link to the history list in wiki