R1:14dab3f55c26

Convert ButtonBar to FontAwesome

Summary: Removes the sprites and images, uses fontawesome in examples and calendar

Test Plan:
UIExamples, Calendar

{F163375}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9371