Maintenance release

[FEATURE] Added email signature field to organizer #669 (thanks @christophlehmann)
[FEATURE] Added room field to event #668 (thanks @christophlehmann)
[BUGFIX] Categories in category menu not translated #670 (thanks @dpool)
[BUGFIX] Respect combination of start- and endDate in searchDemand #672
[TASK] Removed usage of exclude fields for plugins #667
[TASK] Added missing label for plugin setting "recursive"
[TASK] Stream CSV export on the fly #665

[DOC] Updated documentation about new fields for event and organizer