Stream to log

@vezzi I think this will log all the Piper output via the standard minimal_logger we use for everything else. I couldn't test it because nestor is being funky and I think there's some permissions issue. Maybe you can try it out or I'll give it another shot on Monday.
This is good, did you check [logbook](http://log-book.readthedocs.org/en/latest/api/queues/#logbook.queues.ThreadedWrapperHandler) though?