Removed netty dependency. It is only needed by netty-socketio and should
not be required in our POM explicitly.
Updated jackson-databind dependency to version 2.2.2.

These changes hopefully fix the threading problems with redeployment on
Tomcat 7.

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.

Jenkins tries to use old version 2.1.1 but this artifact is not
available anymore.

(Jetty) environment.
Reduced logging for production environment.

This reverts commit 6445fea1.

This reverts commit b2d929f8.