R1:7aea37c44347

PHUIIconView

Summary: Adds a base class for displaying images and icons.

Test Plan: Tested giving and taking tokens, viewed action headers, uiexamples for icons, workboards.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5736