R1:c1e9b20d789c

differential now displays date created and date modified info

Summary: Added date created and date modified to diff

Test Plan: Creat a new diff. Check to see that dateCreated and dateModified appear

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4756