add feature list to readme

Author: feross

README.md

@@ -14,6 +14,11 @@ participate in the torrent.
 Also see [bittorrent-dht](https://github.com/feross/bittorrent-dht). This module is used
 by [WebTorrent](http://webtorrent.io).
 
+## features
+
+- Includes client & server implementations
+- Supports UDP protocol ([BEP 15](http://www.bittorrent.org/beps/bep_0015.html)) (client only, for now)
+
 ## install
 
 ```