add some kind of logging to beanstalk

It has the verbose flag but that's perhaps more accurately called 'debug'. In any event it goes to stdout so that's no good for my purposes and the messages themselves could do with some work.

To that end I've integrated syslog (well, nearly done) because we needed logs to diagnose a problem with no more data to go on than the time it happened and that the server became unresponsive and I didn't want to be in that position again.

So this is mostly a question of whether there is wider interest in this patch, in particular because if there is I'd like to first go through and combine the twarn, verbose and syslog interfaces (and perhaps make a few small disparities I found consistent). In my version, because it's in-house and only for after-the-fact diagnosis, I've simply redirected (entirely) their outputs to syslog and left it at that.