Fixed initialization bug when creating a new participation
(cherry picked from commit b319f49)
Code analysis an optimize imports
(cherry picked from commit 41074bf)
Fixed type error in comparison
(cherry picked from commit f0c0712)
Showing last sign-up date in the event list in the group view
(cherry picked from commit cf85484)
Sorting future events on last signup date instead of start time
(cherry picked from commit 20c34e3)
Sorting all events with the oldest one at the bottom (and new/future ones at the top)
(cherry picked from commit eefa68e)