[WIP] Logging on JNI level

In order to be able to debug on the JNI level, we can log to the ordinary Android log. In this PR, I have added logging of all calls to shared group method. This is work-in-progress - we should be able to log all calls in the other modules and log values of essential variables and parameters.

@bmunkholm @cmelchior @emanuelez 
In particular for open and close it will be nice with the nativePtr. I suggest a special version of the macro for including that, as that will be needed many places.