One more thing that allready should have been in documentation but
drives developers and admins into madness.

This should prevent concurrent ConcurrentModificationException after
application lock on undeploy.

This patch intends to close all websocket connections on bean
destruction of ARSnovaSocketIOServer.

This reverts commit c22330fd.

This enables access to all UserSessionService objects from within the
application. This could be used to send events to all session users.

With this patch all feedbacks will be stored in memory without any
interaction with CouchDB. Due to in memory storage, all feedbacks will
be removed if server gets restartet.

Depending on new requests, feedbacks will be deleted after some time. 

This patch uses an in memory storage of logged in users. Every time
users send a (online) heartbeat the last known active timestamp of all
users will be checked and inactive users will be removed from active
user list.

With this patch, websocket feedback data will be send without using
UserService arrays within ARSnovaSocketIOServer except
reportDeletedFeedback().

CouchDB tries to set _conflicts propertiy but did not find a setter and
throws NoSuchMethodException. This patch will avoid exception throwing.

The reason of exception throwing can be found can be found in CouchDBs
availibility to store different and concurrent versions of one single
document. This error occurs if two different versions of one session
document are stored within CouchDB.

Further we have to take care, that there is only one version of a
session, not multiple versions.

Spring 3.2.2 is less restrictive in view resolving than newer 3.2.3 so
use this until forwarding in ARSnova is fixed to pass 3.2.3.

There is no request parameter name set, so forwarding will fail. Fixed
by this patch.

There is one major bug in websocket implementaton crashing the
application on websocket disconnect caused by NullPointerException.

It seems that disconnect is done after some dependencies are closed.
This might be caused by data serialisiation.