Make the same thing, but for thunderbird

[cleeland]

I've actually forked the repo and tried simply replacing the GUID in install.rdf with that of t-bird. It installs just fine, but does not prevent Ctrl-Q from quitting thunderbird. I'll go through the steps at

https://developer.mozilla.org/en-US/Add-ons/Thunderbird/Building_a_Thunderbird_extension

as a guide to see if I can get it to work, but maybe you could explain how the bootstrap.js hooks in and captures the ^Q?