BarrierSpec Coordinator tests
added a simple cluster sample
fixed two severe Akka.Cluster bugs

1. ClusterDaemon was using Props for `JoinSeedProcess` and
`FirstSeedProcess` that didn't have correct constructor arguments. Fixed
2. `Serialization` did not have correct sorting for evaluating bound
serializers - added a shim that evaluates all specific serializers first
before the object serializer.
rolled back to Helios 1.3.5
merged changes with smalldave
Merge branch 'smalldave-akka-cluster' into akka-cluster
Merge branch 'akka-cluster-samples-dave' into akka-cluster
added a role-based example