BUGs/Hacks:
- FIXME: the MessageDriverSettings API uses a little hack to allow adding new entries to sub-messages without replacing the old one

Short-term TODOs:
- add "Protocols" tab
- add "Extras" tab for changing dial-behaviour (auto-redial, dial-on-demand, etc.)
- add "Revert changes" button
- load add-ons
- write IP (IPCP) protocol add-on
- write PAP authenticator add-on
- write PPPoE device add-on
- move DEVNOTES into a doxygen file and document the rest of the API

Long-term TODOs:
- allow selecting multiple authenticators
