Update Macro for EditEngine

Summary: Updates Macro to use EditEngine. Also removes "URL" field for adding a Macro, which I think it's worth pursuing.

Test Plan:

• Create a Macro
• Forget to name it
• Try a PDF
• Use a Macro
• Edit a macro (not working)

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17821