Rename image to reproducible/base. Rename user to repro (less typing).

Add dependency between .py files in dexy. Set loglevel to DEBUG. Tweak
build-and-run.sh script.
Merge branch 'master' of github.com:reproducible-research/scipy-tutorial-2014
Improved formatting and added subsections.

To better explain how we are getting the image from the Figshare REST API.