make EventHandler non-global

- add Logging trait for nicer interface
- add EventHandlerLogging class for offering the nice interface from
  app.log
- add eventHandler instance to app and use that for all internal logging
  (this means that some places (dispatchers, remoting) were infiltrated
  by app just to do logging, but I think we'll need app in there soon
  enough for other reasons)

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

@@ -19,8 +19,8 @@ import akka.AkkaApplication
  * @author Roland Kuhn
  * @since 1.1
  */
-class TestActorRef[T <: Actor](application: AkkaApplication, props: Props, address: String)
-  extends LocalActorRef(application, props.withDispatcher(CallingThreadDispatcher.global), address, false) {
+class TestActorRef[T <: Actor](_app: AkkaApplication, props: Props, address: String)
+  extends LocalActorRef(_app, props.withDispatcher(new CallingThreadDispatcher(_app)), address, false) {
   /**
    * Directly inject messages into actor receive behavior. Any exceptions
    * thrown will be available to you, while still being able to use