Add, remove or update and existing certificate

Updated for testing (for now)
This will eventually be run periodically and/or server
as a way to generate certificate requests from the commandline

Adding, removing and updating certs

Conflicts:

	lms/djangoapps/certificates/models.py

Get node.js from a more up-to-date PPA.

Feature/ned/quieter tests

Put the coverage data files in the reports dir, where they will be treated like the disposable things they are.

Split out requirements that come from the local mitx repo and those that come from github, and upgrade the local requirements before running tests