Only add source after dependency download

This lets docker cache the ADD instruction, giving us a faster build.
Also, install docker-gen directly to /usr/local/bin.
Merge pull request #32 from shopa/faster-build

Only add source after dependency download
Upgrade to docker-gen 0.3.3
Update Dockerfile
Upgrade Bash

Updated Dockerfile in order to update/upgrade bash to fix the security bug found by Red Hat https://securityblog.redhat.com/2014/09/24/bash-specially-crafted-environment-variables-code-injection-attack/
Merge pull request #35 from vegasbrianc/master

Added the updated Bash
Merge pull request #1 from jwilder/master

MAJ 1