Changing some things about the Dockerfile(s)

to have them build from different base images, switch from a cron image
for registration to an image that only ships tory-register, leaving
looping and whatever to the outside.
Merge remote-tracking branch 'origin/master' into docker-image-touchup
Merge pull request #29 from modcloth/docker-image-touchup

Changing some things about the Dockerfile(s)