User Session Expiration warning

5 minutes prior to a user's session expiration (as best the client-side javascript can tell), the user is notified by a count-down pop-up window their session is about to expire and gives them the chance to continue the session.  The user will see a window similar to

This functionality is normally included by default by the inclusion of the session-timeout portlet in the pre-header region of the quickstart-entities/authenticated-lo.fragment-definition.xml file.