Initial Docker support

A fun weekend project. :)

This gives us a simple, out-of-the-box setup process.  We build an
image, and people can deploy & configure it elsewhere.

See https://www.docker.io/ for general info.

It's still pretty new, but if you boot a modern Linux machine (e.g.
Debian sid), install docker.io with a recent kernel (~3.14), then run
"make docker-quickstart", you should get a nice localhost-only instance.

Run "make help" to see full help, and look at the Makefile to see how
this works.

Also, pull some samples out of the documentation so that we can
reference them.

The pull request is actually just for the most recent commit, but I guess GitHub won't let you make pull requests against commits you haven't merged yet.