Add overflow: hidden back to obj-list

Summary: Long titles tend to break some of the layout. I removed this fixing another bug, but ultimately we changed directions on boards and it doesn't repro anymore.

Test Plan: Test workboards with tasks on and off the screen. All are drawn. Test the homepage with lots of overflowing information. Make sure objects don't break the 'card'.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9020