Transactions - add "view raw" action
Summary: Use cutlery icon for hilarity. Ref T5768.
Test Plan: made something with remarkup in it, used 'view raw' and saw the remarkup raw in a nice little dialogue.
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T5768
Differential Revision: https://secure.phabricator.com/D10183