adding ability to refund or cancel an order

includes:
- renaming order_payment to order_transaction
- added user_id to the transaction log
using total rows formatted values
removing comments
fixing exception handling when processing payments
displaying the final total on the order list
adding option to send email on cancel & refund order
Merge branch 'refs/heads/kohana_v3.3/feature/order_refunds' into kohana_v3.3/master