Add reload notification

[zeisss]

The BasicClient should listen for a reload notification, which triggers a reload, if the user is idle.

Also there needs to be a script which generates this reload for all sessions.

[zeisss]

I implemented a session_timeout notification if the client reconnects after being offline (5min). All models now reload their data when this notification occurs, so the client should have less problems "reconnecting" when being disconnected / offline.