More Differential PHT
Summary: I think I've gotten like 95% of Differential now. Some outliers that need rethinking.
Test Plan: Bring up a new diff, edit a diff, search and sort diffs.
Reviewers: epriestley, btrahan
Reviewed By: epriestley
CC: aran, Korvin
Differential Revision: https://secure.phabricator.com/D4623