Summary: Ref T8300, Rescheduling events by dragging them in day view
Test Plan: Open day view, drag events, observe them reschedule.
Reviewers: chad, epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Maniphest Tasks: T8300
Differential Revision: https://secure.phabricator.com/D12988
