akka cluster ability.
we can use the AkkaClusterRunner to start the backend routees - so they will be able to create a cluster.
on the front end I have created the FEAkkaClusterTransport for uploading the cluster configuration so that the FE actor system will be joining a cluster with routees as his BE.
upgrading the akka version to the new 2.3.2 and adding the cluster jar for supporting the clustering.

The akka dependency has moved to the common project for avoiding duplications.