* Changed signatures and constructor of MessageDispatcherConfigurator
* Changed Dispatchers.lookup, keep configurators instead of dispatchers
* Removed most of the Dispatchers.newX methods, newDispatcher is still there because of priority mailbox
* How should we make it easy to configure priority mailbox?
* Changed tons tests
* Documentation and ScalaDoc is not updated yet
* Some tests in ActorModelSpec are temporary ignored due to failure
* Added JavaActorContext, UntypedActor.getContext
* implicit val context in Actor needs to be implicit to support forward,
it would be nice if it wasn't implicit because now I can't override context
in UntypedActor
* Removed implicit def system in Actor
* Removed implicit def defaultTimeout in Actor
* Removed receiveTimeout, children, dispatcher, become, unbecome, watch,
unwatch in Actor
* Removed corresponding as above from UntypedActor
* Removed implicit from dispatcher in ActorSystem
* Removed implicit def timeout in TypedActor
* Changed receiveTimeout to use Duration (in api)
* Changed many tests and samples to match new api
- create ActorSystemImpl trait to make ActorSystem fully abstract
- add Java API for constructing (ActorSystem.create(...))
- only go through factory methods because .start() has become necessary
- rename all user-facing occurrences of “app” to “system” (Actor trait
and TestKit/AkkaSpec)
- pass ActorSystemImpl to ActorRefs upon creation, which means that
actorOf() and friends need such an argument, which must be provided to
the ActorRefProvider by the ActorRefFactory implementation
- removed SelfActorRef
- added an ActorContext interface that provides a view into ActorInstance
- the ActorInstance (as ActorContext) gets injected into the Actor
- moved self methods like sender and reply directly to the Actor
