Summary: Closes T7935, Calendar events should now auto-invite the creator.
Test Plan: Create event, save, event should now show creator as an invitee.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Maniphest Tasks: T7935
Differential Revision: https://secure.phabricator.com/D12613
