Akka v0.7 live release

#### 0.7.0 Oct 16 2014
Major new changes and additions in this release, including some breaking changes...

__Akka.Cluster__ Support (pre-release) - Akka.Cluster is now available on NuGet as a pre-release package (has a `-pre` suffix) and is available for testing. After installing the the Akka.Cluster module you can add take advantage of clustering via configuration, like so:

    akka {
        actor {
          provider = "Akka.Cluster.ClusterActorRefProvider, Akka.Cluster"
        }
        
        remote {
          log-remote-lifecycle-events = DEBUG
          helios.tcp {
        hostname = "127.0.0.1"
        port = 0
          }
        }
        
        cluster {
          seed-nodes = [
        "akka.tcp://ClusterSystem@127.0.0.1:2551",
        "akka.tcp://ClusterSystem@127.0.0.1:2552"]
        
          auto-down-unreachable-after = 10s
        }
      }


And then use cluster-enabled routing on individual, named routers:

    /myAppRouter {
     router = consistent-hashing-pool
      nr-of-instances = 100
      cluster {
        enabled = on
        max-nr-of-instances-per-node = 3
        allow-local-routees = off
        use-role = backend
      }
    }

For more information on how clustering works, please see https://github.com/akkadotnet/akka.net/pull/400

__Breaking Changes: Improved Stashing__ - The old `WithUnboundedStash` and `WithBoundedStash` interfaces have been slightly changed and the `CurrentStash` property has been renamed to `Stash`. Any old stashing code can be replaced with the following in order to continue working:

    public IStash CurrentStash { get { return Stash; } set { Stash=value; } }

The `Stash` field is now automatically populated with an appropriate stash during the actor creation process and there is no need to set this field at all yourself.

__Breaking Changes: Renamed Logger Namespaces__ - The namespaces, DLL names, and NuGet packages for all logger add-ons have been changed to `Akka.Loggers.Xyz`. Please install the latest NuGet package (and uninstall the old ones) and update your Akka HOCON configurations accordingly.

__Serilog Support__ - Akka.NET now has an official [Serilog](http://serilog.net/) logger that you can install via the `Akka.Logger.Serilog` package. You can register the serilog logger via your HOCON configuration like this:

     loggers=["Akka.Logger.Serilog.SerilogLogger, Akka.Logger.Serilog"]

__New Feature: Priority Mailbox__ - The `PriorityMailbox` allows you to define the priority of messages handled by your actors, and this is done by creating your own subclass of either the `UnboundedPriorityMailbox` or `BoundedPriorityMailbox` class and implementing the `PriorityGenerator` method like so:

    public class ReplayMailbox : UnboundedPriorityMailbox
    {
        protected override int PriorityGenerator(object message)
        {
            if (message is HttpResponseMessage) return 1;
            if (!(message is LoggedHttpRequest)) return 2;
            return 3;
        }
    }

The smaller the return value from the `PriorityGenerator`, the higher the priority of the message. You can then configure your actors to use this mailbox via configuration, using a fully-qualified name:


    replay-mailbox {
     mailbox-type: "TrafficSimulator.PlaybackApp.Actors.ReplayMailbox,TrafficSimulator.PlaybackApp"
    }

And from this point onward, any actor can be configured to use this mailbox via `Props`:

    Context.ActorOf(Props.Create<ReplayActor>()
                        .WithRouter(new RoundRobinPool(3))
                        .WithMailbox("replay-mailbox"));

__New Feature: Test Your Akka.NET Apps Using Akka.TestKit__ - We've refactored the testing framework used for testing Akka.NET's internals into a test-framework-agnostic NuGet package you can use for unit and integration testing your own Akka.NET apps. Right now we're scarce on documentation so you'll want to take a look at the tests inside the Akka.NET source for reference.

Right now we have Akka.TestKit adapters for both MSTest and XUnit, which you can install to your own project via the following:

MSTest:

    install-package Akka.TestKit.VsTest

XUnit:

    install-package Akka.TestKit.Xunit