Feature/persistence

Established basic framework  for persistence. It should now be able to restore it's state after a shutdown. I opted for the simplest possible solution right now were the journal is written to disk, so if we have a catastrophic failure where we lose the entire machine we including the storage we'll lose the masters state, but on the other hand this saves us the trouble of setting up a distributed data store for this - and as long as we backup the place on disk were the journal is kept we should still be able to roll back.