Docker build with nfd starting successfully

For whatever reason `ndn-start` appears to do nothing. `ndn` however starts up just fine.

This Dockerfile just runs `ndn` in the foreground. You'd have to use [nsenter](http://blog.docker.com/2014/06/why-you-dont-need-to-run-sshd-in-docker/) to get a shell. Alternately, we could try running `ndn` as a daemon via Upstart ([deprecated](http://www.markshuttleworth.com/archives/1316)), Supervisor, Daemontools, or similar.

Also removes a bunch of redundant info from the README.