ReplyTo EPR must be manually reset after Aggregator action is used

The ESB depends on the message's replyTo to know where to send a reply in a RequestResponse service. However, the Aggregator action makes no attempt to preserve the replyTo when it creates an aggregate message for a series. In most cases, I would think the replyTo on the aggregated messages would be the same, so adding it onto the resulting aggregated message would seem like a good idea. Otherwise, it has to be handled manually in the assembler action.