Implement clean and consistent logging

[yschimke]

The current logging is on JVM Platform only. Nothing hooked up in Android.

A few things to look at

1. ensure logging is consistent. Currently there may be important events or attributes not logged like the reason a stream was rejected.
2. consider adopting slf4j for JVM platform. this might involve multiple modules to avoid dragging this in for Android.
3. implement an appropriate logging mechanism for android that matches that automatically puts logging in the right place.