Summary:
Provide a viewer to all remarkup engines.
This fixes commit summaries in Diffusion, which were failing to link because they didn't have a user and thus couldn't see/load `D123`, e.g.
Test Plan: Grepped for engine creation.
Reviewers: vrana
Reviewed By: vrana
CC: aran, edward
Maniphest Tasks: T603
Differential Revision: https://secure.phabricator.com/D5152
Summary:
D5120 and followups refactor and generalize object references in Remarkup -- notably, they move remarkup rules from a central location to the implementing applications.
Preserve blame by doing moves/renames only first. This change moves application remarkup rules into those applications, and renames the ones D5120 modifies.
Test Plan: Typed some preview text into a textarea, got a valid Remarkup render.
Reviewers: vrana, chad
Reviewed By: vrana
CC: aran
Differential Revision: https://secure.phabricator.com/D5123
