Copying events needs to create new copy of price set

See bug report from sonicthoughts at http://forum.civicrm.org/index.php/topic,26445.msg112131.html#msg112131

Three use cases: copying of event template to event template, copying of event template to event, copying of event to event. In all three cases, it is necessary to replicate the price set associated with the original event and use the copy of the price set with the new event template or event.