Put dockerui in the PATH in the docker container

This seems a cleaner way to start the daemon.

Even better would be if the daemon had a sensible default for the docker address, it could then be added as a CMD in the Dockerfile. It seems that the docker0 bridge's address is 172.16.42.1, if docker binds on that IP address then we could default to "-e="http://172.16.42.1:4243""