vividtone Add assignee's icon to tooltips in gantt and calendar (#29306).
Patch by Mizuki ISHIKAWA.


git-svn-id: http://svn.redmine.org/redmine/trunk@17493 e93f8b46-1217-0410-a6f0-8f06a7374b81
Latest commit 4a5a68f Sep 19, 2018