Add some missing requirements to the dep list.

I tried setting up nuancier in a fresh virtualenv with
``pip install -r requirements.txt``, but python-fedora didn't pull in
these deps.  We should add them here to make it as easy as possible for
people to hack on our apps.

Relates to #33.
Merge pull request #39 from fedora-infra/missing-requirements

Add some missing requirements to the dep list.