Add clone() and toString() to all events

Need to add a clone() method to all event classes that have custom properties so that when redispatched the event keeps these properties.

Best practices would have you add the clone() and toString() methods to all events.

Without the clone() method in the event classes, your redispatched event will be of standard type Event and no longer the typed event (eg: XIFFErrorEvent) which leaves you without the custom properties (eg:errorMessage).