Nchan, a pub/sub module for Nginx: 64K websockets in .2sec

After last week's discussion [1], I've made some improvements and bumped up this project from alpha to beta status. I've also run some benchmarks, and they're reasonably impressive. New subscribers, HTTP multipart/mixed and chunked-encoding, have also been added.

[1] https://news.ycombinator.com/item?id=10685946