Feature #466: IPAACA v3
v3: Expose more event data
In v2, IU events handlers were restricted to the signature handle_event(iu, evt_type, local), not being able to access event metadata (deltas, modified / deleted keys, owner name). A new, parallel, handler signature / registration is to be implemented that exposes all these data to the application developer. Compatibility of old application source code should be maintained as far as possible.