This adds the `select` and `unselect` events so users can still
hook into them from their jQuery plugins.
This also modifies the core `trigger` to fire pre-events that can
be canceled for the `open`, `close`, `select`, and `unselect`
events. Users implementing these events who need to handle cases
where the event has been prevented should check `args.prevented`,
where `args` is the object that was included for arguments when
triggering the internal event.
