added an operation to the dotlrn_applet service contract. the operation's name is ChangeEventHandler and is usually implemented by change_event_handler method in the dotlrn_applet implementation. dotLRN can throw events based on changes to a community via the dotlrn_community::generate_change_event method.
currently the only event being thrown and handled is the 'rename' event. this event is thrown when the name of a community is changed. the only applets that currently listen for this event are dotlrn_fs, dotlrn_forums, and dotlrn_calendar.
applets do not have to handle all events, only events they are interested in handling.
fixed dotlrn::is_package_mounted to check if the package is mounted directly under dotlrn, i.e. /dotlrn/bulk-mail, not /dotlrn/classes/foo/bar/bar-summer-2002/bulk-mail. if any code depended on this broken behaviour then that code will have to be fixed.