Reduced memory footprint to less than 4gb to fit on a mac mini. Added apt cacher restart to ensure it's running when the cache node boots up, since if it's not for some reason then everything will fail as apt-get update breaks on every node. Because the cache node will likely be halted and not destroyed when a user wants to stop the environment, this needs to work every time.
Added a commented section for importing the base precise image from a local source instead of the US mirror.