Code for handing refunds (returning settled transactions to the credit card)
 - also adding tracking to see which admin last updated a payment (or inserted it for that matter)
Adding better exception handling for refunds
Add support for transaction voids.  This will cancel transactions that have not yet settled by authnet.  It will be invoked if the Refund attempt fails
First round of PR fixes
Removing false check in this test
Adding javadoc