Akka.NET v0.6 release

This version of Akka.NET contains some new features, such as the `ScatterGatherRouter`, and a long list of bugfixes.

Here's the nitty-gritty:

* Upgraded the `Helios` dependency to v1.2.3, which has been performing reliably under high loads for the past two weeks in production for my analytics startup. This resolves a number of Akka.Remote issues, the biggest one being that messages above 5120b cause an unexpected network error.
* Improved the error-handling behavior for `HeliosTransport` in Akka.Remote - non-fatal network errors (such as a malformed message) no longer cause the connection to reset and those errors are properly logged to the eventstream now.
* Added support for virtualized IP addresses, which allow inbound actors to listen for connectivity on different network interfaces. You can read more about this here: #134
* Remote deploy now works as expected
* Added `ScatterGather` router
* Added Mailbox Suspend / Resume during actor restarts
* Fixed the Become / Unbecome behavior stack
* Fixed some `ActorSelection` bugs, and also added the `resolveOne` method - which will allow you to determine whether or not your `ActorSelection` is valid ahead of time.

You can download the latest from here: https://www.nuget.org/packages/Akka/

We're creeping towards a full v1.0 release soon, but v0.6 has been able to work well in production for my team under considerable production loads.