Disabled AOP code executed when joining sessions which caused an
exception because of scoping.

It is required to setup those values after login. Current session
information will be set up after joining a session.

This could be used to send data via websockets without searching
sessionIDs or user tables within ARSnova.

Simply publish an event with ARSnova-sessionKey from within the
application.

This sets current user and ARSnova session information in a session
scoped service bean. If the user connects with a websocket, the
websocket session ID will be set in addition to the user and session
object.

The aspects methods pointcut after returning from joinSession() method
in SessionService. So the UserSessionService will be set with all needed
data after a user successfully joins a session.

With this service available, it can be used to replace some usage of
Array/Map based application wide data structures that cause some trouble
when stopping or redeploying the application.