Support for starting/stopping application from linux command line using mono-service.exe

Allows user to start application using mono-service.exe and have proper start/stop behavior.
This looks a bit strange, as when running under windows this is not going to be called (ie. there's a differente HostEnvironment already provided by Topself). And when running as a simply command line process the obvious choice is not calling topshelf's initialization method.

So, in which case does your code en up reaching this point? Maybe this is due to some newer feature/change whithin on Topshelf itself which I am not aware of?