Convert Durable Column to popup chat in footer
Summary: This feels pretty reasonable with little effort, and I think I'd use it more than the full column.
Test Plan:
Chat a lot on various pages.... still some quicksand quirks around various pages.
{F1853487}
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: scp, Korvin
Differential Revision: https://secure.phabricator.com/D16627