:  * @abstract Informs the delegate that a Growl notification was clicked.  * @discussion Informs the delegate that a Growl notification was clicked.  It  *  is only sent for notifications sent with a non-<code>nil</code>  *  clickContext, so if you want to receive a message when a notification is  *  clicked, clickContext must not be <code>nil</code> when calling  *  <code>+[GrowlApplicationBridge notifyWithTitle: description:notificationName:iconData:priority:isSticky:clickContext:]</code>.  * @param clickContext The clickContext passed when displaying the notification originally via +[GrowlApplicationBridge notifyWithTitle:description:notificationName:iconData:priority:isSticky:clickContext:].  */ - (void) growlNotification