First tiny steps toward version counters (will be used in activities).
saveWithVersion now inserts an object that is not yet present in the database.
Objects without version conflicts are updated properly, and the version counter is incremented.
Version conflicts are now indicated via error message.
Using the new function saveWithVersion, we can now demonstrate how Bug 578 can be resolved in principle.
Activities are now saved with version.
Test configuration that allows to use real persistence stores.
addVisitor can now cope with version conflicts due to racing conditions.
removeVisitor can now cope with version conflicts due to racing conditions.
addToWaitinglist can now cope with version conflicts due to racing conditions.
removeFromWaitinglist can now cope with version conflicts due to racing conditions.
Moved DB tests to separate directory where there is no conflict with non-DB setup.
Review: Improved names and comments.
Renamed the activities concurrency test.
Improved some variable names.
Now the waitinglist API handles concurrency conflicts automatically by retrying.
Added the new tempbeans file to gitignore.
Fixed jshint error.
Merge pull request #580 from NicoleRauch/master

Bugfix für #578: Jetzt werden Racing Conditions beim Speichern abgefangen
Added button for participants of an activity and changed button of the waiting list.