When the notebook starts up, it opens a browser with its homepage.
Currently, this simply makes the call to launch the browser immediately before entering the server loop. On my system, the server is running by the time the browser requests the homepage. If this isn't sufficient, we'll just need to use a threading.Timer to delay it for a fraction of a second.
There's a config option, and a flag --no-browser to control this behaviour.
Add ability to open the notebook in a browser when it starts.