* Assign internal upNumber when member is moved to Up
* Public API Member.isOlder
* Change cluster singleton to use oldest member instead of leader
* Update samples and docs
* Deprecate all actorFor methods
* resolveActorRef in provider
* Identify auto receive message
* Support ActorPath in actorSelection
* Support remote actor selections
* Additional tests of actor selection
* Update tests (keep most actorFor tests)
* Update samples to use actorSelection
* Updates to documentation
* Migration guide, including motivation
* Config of node roles cluster.role
* Cluster router configurable with use-role
* RoleLeaderChanged event
* Cluster singleton per role
* Cluster only starts once all required per-role node
counts are reached,
role.<role-name>.min-nr-of-members config
* Update documentation and make use of the roles in the examples
* ClusterSingletonManager
* ClusterSingletonManagerSpec multi-node test
* Use in cluster router with single master sample
* Extensive logging to be able to understand what is
going on
* Java api
* Add cluster dependency to contrib
* Add contrib dependency to sample
* Scaladoc
* rst docs in contrib area, ref from cluster docs
