implement remote routers

- split out actual routing functionality into *Like traits to be
  reusable
- make RemoteRouterConfig which only differs in how remote placement is
  initiated
- teach RemoteDeployer how to convert local RouterConfig in case config
  key “target.nodes” is set
- IT WORKS! All tests GREEN
- oh, yeah, had to make ActorPath serializable ...

akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala

@@ -1,3 +1,6 @@
+/**
+ * Copyright (C) 2009-2011 Typesafe Inc. <http://www.typesafe.com>
+ */
 package akka.routing
 
 import java.util.concurrent.atomic.AtomicInteger