Failure detector refactoring, see #2690

* Failure detector was previously copied with refactoring to
  akka-remote and this refactoring makes use of that and removes
  the failure detector in akka-cluster
* Adjustments to reference.conf
* Refactoring of FailureDetectorPuppet
Merge pull request #1086 from akka/wip-2690-remote-fd-patriknw

Failure detector refactoring, see #2690