Improved exception handling for the GUI

Occuring (runtime) exceptions are currently just (implicitly) thrown by the controllers. Although not visible on the GUI, the stack trace is not logged but visible in the console. An improved exception handling would be advisable, including an approach that covers everything. I am thinking about Proxys, AOP, or even generated code to add the exception handling to the controllers. In case of an exception, a dialog should inform the user, and the stack trace should be logged.