Introduce parental supervision, BUT TESTS ARE STILL FAILING

- every actor is now supervised, where the root of the tree is
  app.guardian, which has its supervisor field set to a special ActorRef
  obtained from provider.theOneWhoWalksTheBubblesOfSpaceTime (this name
  is meant to indicate that this ref is outside of the universe, cf.
  Michio Kaku)
- changed all tests to obtain specially supervised children (i.e. not
  top-level) via (supervisor ? Props).as[ActorRef].get
- add private[akka] ScalaActorRef.sendSystemMessage for sending
  Supervise()
- everything routing or remote is broken wrt. supervision, as that was
  not “properly” implemented to begin with, will be tackled after
  app/supervision/eventbus/AkkaSpec are stabilized enough

akka-testkit/src/main/scala/akka/testkit/TestFSMRef.scala

@@ -34,8 +34,8 @@ import akka.AkkaApplication
  * @author Roland Kuhn
  * @since 1.2
  */
-class TestFSMRef[S, D, T <: Actor](app: AkkaApplication, props: Props, address: String)(implicit ev: T <:< FSM[S, D])
-  extends TestActorRef(app, props, address) {
+class TestFSMRef[S, D, T <: Actor](app: AkkaApplication, props: Props, supervisor: ActorRef, address: String)(implicit ev: T <:< FSM[S, D])
+  extends TestActorRef(app, props, supervisor, address) {
 
   private def fsm: T = underlyingActor
 
@@ -81,8 +81,8 @@ class TestFSMRef[S, D, T <: Actor](app: AkkaApplication, props: Props, address:
 object TestFSMRef {
 
   def apply[S, D, T <: Actor](factory: ⇒ T)(implicit ev: T <:< FSM[S, D], app: AkkaApplication): TestFSMRef[S, D, T] =
-    new TestFSMRef(app, Props(creator = () ⇒ factory), Props.randomAddress)
+    new TestFSMRef(app, Props(creator = () ⇒ factory), app.guardian, Props.randomAddress)
 
   def apply[S, D, T <: Actor](factory: ⇒ T, address: String)(implicit ev: T <:< FSM[S, D], app: AkkaApplication): TestFSMRef[S, D, T] =
-    new TestFSMRef(app, Props(creator = () ⇒ factory), address)
+    new TestFSMRef(app, Props(creator = () ⇒ factory), app.guardian, address)
 }