R1:a939bbc4fa21

Update EditEngine for two column

Summary: Cleans up EditEngine, adds new layout to EditEngine and descendents

Test Plan: Test creating a new form, reordering, marking and unmarking defaults. View new forms.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15531