* Split config reference to one for each module/extension.
* Adjusted signature of registerExtension to avoid race of extension init
* Moved Duration.dilated to testkit
* TestKitExtension
* RemoteExtension
* SerializationExtension
* Durable mailboxes extensions
* Fixed broken serialization bindings and added test
* Updated configuration documentation
* System properties akka.remote.hostname akka.remote.port replaced with akka.remote.server.hostname and akka.remote.server.port
* Adjustments of ActorSystem initialization. Still don't like the two-phase constructor/init flow. Very fragile for changes.
Review fixes. SerializationExtension
someone should look at remoting vs. timeout (i.e. which is sent around),
because I removed that in some places. It might simply be irrelevant
once we remove the Future special-casing.
