This change includes:

 - (on possibly older python versions ?) a string variable test using the 'is' operator fails (so it always return ok immediately after initial delay)
 - add a missing socket.settimeout() for the state=started case (if the machine does not exist, timeout defaults to 60 seconds)
 - add a connect_timeout option to customize the default connection timeout
 - use socket.shutdown(2) to close immediately
 - return the elapsed time