Implement signal/slot mechanism

[cinc]

Signals and slots should be provided in some form. I imagine some generic form where every object method may be a slot for a signal. So one does not have to specify this in the IDL file. One may think about the opposite. Methods not suitable as slots are marked specially.

Connecting signals to a method is done using a special method of NOMObject. This method checks for compatibility signal<->slot and performs the necessary actions.