don't allow users to lock an already locked model
add failing request on version conflicts and locking problems
add out of sync error message
destroy details when model destroyed
Merge branch 'f-actor-groups-features' into f-realtime-improvements

Conflicts:
	app/assets/locales/de.json
Merge branch 'master' into f-realtime-improvements

Conflicts:
	app/assets/locales/de.json
Merge pull request #188 from transparencyint/f-realtime-improvements

F realtime improvements