Make use of "Mnn" in Pholio more consistent

Summary:
  - Drop it from crumb.
  - Add it to pinboard.
  - Drop it from header.
  - Add it to title.

Test Plan: looked at stuff

Reviewers: chad, ljalonen

Reviewed By: ljalonen

CC: aran

Differential Revision: https://secure.phabricator.com/D5068