R1:f9306c2e58db

Add a Nuance content source, and make use of it

Summary: Ref T10537. Add a new content source for Nuance. Prepare for better author attribution.

Test Plan: {F1194038}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10537

Differential Revision: https://secure.phabricator.com/D15539