Don't mix different users on the same line in Calendar
Summary:
The current state is very confusing:
{F11734, size=full}
Test Plan: Display calendar for user with two different events in the same week.
Reviewers: epriestley, btrahan
Reviewed By: epriestley
CC: aran, Koolvin
Differential Revision: https://secure.phabricator.com/D2522