Update Maven scala plugin to 3.1.2
Update to Akka 2.2-SNAPSHOT (failing integration test)

- Netty was updated to 3.6.2.Final (at least 3.6.0 is required by
akka-remote)

- Removed the temporary import on akka.remote.netty in core

- Removed the temporary settings in application.conf

- Changed references to akka-actor to akka-osgi
Merge pull request #5 from vivosys/akka-2.2

Akka 2.2