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.
Just enabling or disabling logging falls short of the power of
interfaces of go. A user is forced to either accept the logging to
stderr in the format defined by xgb or disable logging alltogether. By
exporting the logger, we can actually let the user decide where to log
in what format.
