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