[WM] put an empty env-configs in the repo

This allows docker build to still work out of the box, and will still ignore
all the files in env-configs.
[WM] use docker.io clojure-api-build container as base

The docker-builds containers on quay.io are not built on every commit (though they could be).
[WM] remove apt-get update from Dockerfile

We should only do this in the base container and after adding new repos.
[WM] update package installs in Dockerfile for Ubuntu 14.04
[WM] add /run.sh CMD to Dockerfile

Not sure why this isn't being inherited, but it sure wasn't running that on my local Docker 0.10.0 before I added it here.