Fix some Editor issues

Summary: The property is called 'actor', not 'user'. Extend from Phobject to catch this class of error automatically. Upgrade a couple of getActor() to requireActor().

Test Plan: Created new users.

Reviewers: btrahan, vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D3776