fix more EventFilter related issues

- LoggingBus.startDefaultLoggers would not wait for their
  initialization, leading to non-reception of Mute messages at the very
  start of test, which would in turn fail those test which require a
  number of occurrences.
- fix that by having each logger respond to InitializeLogger(bus) as
  soon as subscriptions are done (max 3 seconds, else Warning)
- make akka.actor.simpleName not use String.replaceAll (performance
  oversight on my part)
- rename MainBusSpec object to EventStreamSpec
- give loggers nicer names: "log<id>-<classname>"

akka-slf4j/src/main/scala/akka/event/slf4j/SLF4J.scala

@@ -49,7 +49,7 @@ class Slf4jEventHandler extends Actor with SLF4JLogging {
       logger(instance).debug("[{}] [{}]",
         event.thread.getName, message.asInstanceOf[AnyRef])
 
-    case InitializeLogger(_) ⇒ log.info("Slf4jEventHandler started")
+    case InitializeLogger(_) ⇒ log.info("Slf4jEventHandler started"); sender ! LoggerInitialized
   }
 
   def logger(instance: AnyRef): SLFLogger = instance match {