UP-3717 - session timeout

Worth a comment here explaining the meaning of this setting right where an adopter would be setting it?  Something like

    <!-- The session timeout warning will start displaying this many seconds before 
           the end of the user's session and will remain on the screen for this many seconds 
           (until the end of the session) 
           at which point the portlet will redirect to the logout URL specified in logoutURLFragment. -->