Service Host should deal with Azure/Windows envrionments

[mattridgway]

To make the code more implicit we should change the service host extension methods so that composition looks like the following:

//Thread falls through after it has run, service would stop
app.OnStart<Xsi.Projector>(projector => projector.Receive).ThenStop();
app.OnStop(projector => projector.Dispose);

//Thread is held after it has run, like listening for new event from hub
app.OnStart<Xsi.Projector>(projector => projector.Receive).ThenBlock();
app.OnStop(projector => projector.Dispose);

//everytime it finishes it loops around and starts again
app.OnStart<Xsi.Projector>(projector => projector.Receive).ThenLoop();
app.OnStop(projector => projector.Dispose);

[smudge202]

This should be pretty easy to accomplish. Basically, by default we'd expose the CancellationToken, but the helpers can manage the token in order to provide the above extensions.

+1

[smudge202]

This needs to be moved to smudge202/compose-azurecloudservice