Pulled in changes from https://github.com/nlevitt/umbra/tree/aitfive-451-alt
Pulled in changes from https://github.com/nlevitt/umbra/tree/aitfive-451-alt

internetarchive/umbra,nlevitt/brozzler,internetarchive/brozzler,internetarchive/brozzler,nlevitt/brozzler,vonrosen/umbra,vonrosen/umbra,internetarchive/brozzler,nlevitt/brozzler,internetarchive/brozzler,nlevitt/brozzler,nlevitt/brozzler