R1:705fd11ba173

Update Legalpad to use modular transactions

Summary: Update Legalpad for modular transactions

Test Plan:
- New Document (no sign)
- New Document (individual)
- New Document (corp)
- Require Signature - get prompted to sign before I can do anything.
- Edit Documents
- Sign Documents
- Comment on Documents

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17826