Summary:
Updates PhabricatorTimeline to PHUITimeline. Uses standard colors and spacing, softens up the actors, and reduces visual spacing of action-only events.
- Also updated some 2x sprite images.
Test Plan: Tested Tasks Paste and Pholio in my sandbox.
Reviewers: epriestley, btrahan
Reviewed By: epriestley
CC: Korvin, epriestley, aran
Differential Revision: https://secure.phabricator.com/D8205
