Remove SelfActorRef and use ActorContext to access state in ActorInstance. See #1202

- 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

akka-camel/src/test/scala/akka/camel/component/ActorComponentFeatureTest.scala

@@ -96,13 +96,13 @@ class ActorComponentFeatureTest extends FeatureSpec with BeforeAndAfterAll with
 object ActorComponentFeatureTest {
   class CustomIdActor extends Actor {
     protected def receive = {
-      case msg: Message ⇒ self.reply("Received %s" format msg.body)
+      case msg: Message ⇒ reply("Received %s" format msg.body)
     }
   }
 
   class FailWithMessage extends Actor {
     protected def receive = {
-      case msg: Message ⇒ self.reply(Failure(new Exception("test")))
+      case msg: Message ⇒ reply(Failure(new Exception("test")))
     }
   }