detect net splits

[splitbrain]

our biggest problem with the bot currently is that it won't detect netsplits and will hang out on an abandoned node until someone comes and restarts it.

It should be possible to detect netsplits by the parting messages of other clients. They seem to post a *.net *.split message in their parting messages. Maybe just die when we see three of these right next to each other?

http://irc.dokuwiki.org/index.php?d=2014-03-07#msg502162