Summary:
Ref T9360. Moves PhamePost to CommentEditEngine.
[x] HTTP Parameters dropdown on New Post goes to 404
[x] Implement EditEngine Comments
Test Plan: Make Post, Make Comment, Laugh.
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T9360
Differential Revision: https://secure.phabricator.com/D16222
