Cleaning up logging in SisyphusMasterActor

Using LoggingReceive instead of explicitly stating logs for incomming
messages. Also changed log levels to that not everything in info, but
gave some log messages debug status and other warning.
Moved all state changes in to separate case

In preparation for persisting the state changes it will be easier if all
state change is handled in a single place.
Basic framework established for persistence.

I think it's working - it
seems to be re-establish it's state after restarts at least. It's quite
possible that this needs some more tuning in the future, but at least
the basics is there
Merge pull request #23 from johandahlberg/feature/persistence

Feature/persistence