R1:fdde45c623e0

Make PHUIIconView extend AprontTagView

Summary: Less code, more options.

Test Plan: Test UIExamples page (action headers, tokens, icons and images). No visible difference.

Reviewers: epriestley, btrahan, vrana

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5742