Summary: Closes T7953, Calendar events should now have a 'Name' field.
Test Plan: Create or edit event with no title, save event, should get error requiring name, event detail view timeline should reflect name changes.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Maniphest Tasks: T7953
Differential Revision: https://secure.phabricator.com/D12591
