SAK-28099; replace presence iframe with a DIV backed by ajax


git-svn-id: https://source.sakaiproject.org/svn/chat/trunk@315701 66ffb92e-73f9-0310-93c1-f5514f145a0a
SAK-28099; set max length to presence, and scroll it


git-svn-id: https://source.sakaiproject.org/svn/chat/trunk@315703 66ffb92e-73f9-0310-93c1-f5514f145a0a