Added the ability to scope tokens to a specific client. If
enabled, this has the affect of limiting the token to being used
to list tunnels for that specific client. It can't be used for
the web UI or for any state-changing actions such as creating
new tunnels.
The UI was originally written using fancy HTML checkbox toggle
hacks in order to make the UI very fast. It's cool but complicated
and difficult to change. In order to make updates to the UI more
quickly, I'm changing it to use traditional HTML with full page
reloads for navigation. It's not as fast but much simpler.
