AUTHORS, CONTRIBUTORS: still useful, add people from git log, clean up.
LICENSE: Google doesn't really grant you shit anymore. The EU doesn't
have software patents either, so it doesn't affect me directly.
README, doc.go: erase mentions of unmaintained xgbutil.
Fixes#9.
This makes shutdown a little more graceful, but there's more
work to be done here. Namely, all outstanding cookies need to
be given the error, otherwise they will block forever.
