UntilServerDoUsApart - implementing logic for starting WebSocket transpo...

...rt on WindowsPhone 8.1.

Note that the CI needs to be updated to be able to build Store product/test projects after they took dependencies on Windows.Networking. I ran FunctionalTests on my machine and they passed. I also have a WP8.1 chat client I tested that the change works E2E (i.e. that the client can connect to the server and receive messages).
Ok after digesting the code again I remember how it works. The nicest way to do this would be:

```C#
Task.Run(async () => 
{
    var url = UrlBuilder.BuildConnect(connection, Name, connectionData);

    try
    {
        await StartWebSocket(connection, url);
    }
    catch (TaskCancelledException)
    {
        initializationHandler.Fail();   
    }
    catch (Exception ex)
    {
        initializationHandler.Fail(ex);
    }
});

return initializationHandler.Task;
```

Task.Run just allows the fire and forget semantics