Build docker images automatically on the first run
Removed command to change /etc/hosts

This was needed for docker version 0.6.1, but in the latest version
(0.6.5) it's no longer needed and in fact causes in an error.
Removed EXPOSE statements from the Dockerfiles

Docker no longer supports specifying the public port in EXPOSE
statements.  Instead, made the scripts use the -p flag when starting
the container to accomplish the same thing.

Added the "shutdown.py --rm" command, which should shutdown the
containers and also remove them.