Audit - tweak colors

Summary: See github issue 413. This diff adds color to the commit view as the user expects *AND* adds green to both audit and commit views. I looked in the history (D6184) and I can't tell how expected green was, but it feels nice to me given differential color coding.

Test Plan: looked at lists of audits and commits with pretty colors.

Reviewers: epriestley, chad

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7900