introducing: MainBus feat. LoggingBus

most tests passing, everything compiling, but docs not updated and nasty
thread-leak preventing me from running the whole test-suite (which is
the reason for this commit: I want to chase down that one first).

- the app.mainbus is classified by Class[_] (currently lookup, will
  possibly change to sub-class-aware) and accepts AnyRef messages
- LoggingBus handles akka.event-handlers from config specially:
  + start them as system services, supervised by SystemGuardian
  + keep their subscriptions in sync when logLevel_= is called
  + send them InitializeLogger(bus) message before subscribing them (so
    they can register for extras like Mute/UnMute)
- two-phased start-up: first phase with actor-less stdout logging, then
  subscription of config loggers, then remove stdout logger (logLevels
  configurable separately)
- MainBusReaper watches registered receivers and unsubscribes them upon
  death (started in phase 2)
- logger factory on Logging object, needs app/bus and log source;
  default instance in app.log

akka-docs/scala/code/ActorDocSpec.scala

@@ -7,15 +7,16 @@ import akka.util.duration._
 
 //#imports
 import akka.actor.Actor
-import akka.event.EventHandler
+import akka.event.Logging
 
 //#imports
 
 //#my-actor
 class MyActor extends Actor {
+  val log = Logging(app, this)
   def receive = {
-    case "test" ⇒ app.eventHandler.info(this, "received test")
-    case _      ⇒ app.eventHandler.info(this, "received unknown message")
+    case "test" ⇒ log.info("received test")
+    case _      ⇒ log.info("received unknown message")
   }
 }
 //#my-actor
@@ -30,23 +31,21 @@ class ActorDocSpec extends AkkaSpec {
     // testing the actor
 
     // TODO: convert docs to AkkaSpec(Configuration(...))
-    app.eventHandler.notify(TestEvent.Mute(EventFilter.custom {
-      case e: EventHandler.Info ⇒ true
-      case _                    ⇒ false
-    }))
-    app.eventHandler.addListener(testActor)
-    val eventLevel = app.eventHandler.level
-    app.eventHandler.level = EventHandler.InfoLevel
+    val filter = EventFilter.custom {
+      case e: Logging.Info ⇒ true
+      case _               ⇒ false
+    }
+    app.mainbus.publish(TestEvent.Mute(filter))
+    app.mainbus.subscribe(testActor, classOf[Logging.Info])
 
     myActor ! "test"
-    expectMsgPF(1 second) { case EventHandler.Info(_, "received test") ⇒ true }
+    expectMsgPF(1 second) { case Logging.Info(_, "received test") ⇒ true }
 
     myActor ! "unknown"
-    expectMsgPF(1 second) { case EventHandler.Info(_, "received unknown message") ⇒ true }
+    expectMsgPF(1 second) { case Logging.Info(_, "received unknown message") ⇒ true }
 
-    app.eventHandler.level = eventLevel
-    app.eventHandler.removeListener(testActor)
-    app.eventHandler.notify(TestEvent.UnMuteAll)
+    app.mainbus.unsubscribe(testActor)
+    app.mainbus.publish(TestEvent.UnMute(filter))
 
     myActor.stop()
   }