Printable pages for PHUIDocumentViewPro

Summary: Fixes T10131. Adds new CSS to better present document pages for printing. Added a print link to Phriction.

Test Plan: Tested Phriction, Phame, and Legalpad.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T10131

Differential Revision: https://secure.phabricator.com/D16524