Feature Request: Provide Websocket Interface as  Cmd Option

**Problem:** 
The websocket is currently bound to all interfaces on 0.0.0.0 and with #23 also to 127.0.0.1 by env variable. One might bind the websocket to a particular interface without further software.

**Solution:** 
Provide a command line option e.g.: `-i 0.0.0.0` which leaves the configuration of the interface up to the user.
