ObjectHeader Status icons

Summary: Adds status icons and colors to Maniphest and Differential. Also minor tweaks to them in hovercards. Probably some other stuff too.

Test Plan: Test many diff and task states.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: Korvin, aran

Differential Revision: https://secure.phabricator.com/D7098