This test uses the standard txtorcon test container.

This test confirms that a TCP4HiddenServiceEndpoint listens only on
the loopback interface. Basically "container_run" uses launch_tor()
and TCPHiddenServiceEndpoint to create a working hidden service. For
bonus points, it runs "netstat -pltn" after the service is set up.

"host_run" (from outside the container) uses nmap to confirm nothing
is listening on the public interface.
