Clean up some rough Macro transaction edges

Summary: Ref T12685, cleans up various macro issues, remove subscribers, fix feed stories, etc.

Test Plan: Create a new macro, see no subscribers, edit various macros.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12685

Differential Revision: https://secure.phabricator.com/D17848