R1:2dfb2cd43239

Add an "Mxx" crumb on the Pholio edit page

Summary: This crumb, which is consistently available in other applications, is not currently available in Pholio.

Test Plan: Viewed an edit page, clicked the crumb.

Reviewers: chad

Reviewed By: chad

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D9542