Fixed a bug in the handling of multiple charges to the same customer
Mercury: Proper refund and void support

Refunds are now Returns, and voids are now VoidSales. Also allows a
"Reversals" via a custom option to #void, which are faster voids.

Closes #784.
Correctly calculates PP Express discounts for non-decimal currencies
Merge pull request #771 from Shopify/fix-paypal-non-decimal-discounts

Correctly calculate PayPal Express discounts for non-fractional currencies
PaymentExpress: Return token in authorization

In keeping with the standard #store API this makes PaymentExpress return
the token in the Response#authorization field. The custom Response#token
method has been left in place for backwards compatibility.
Capture method of NAB Transact gw should support options param
Stripe: Add ability to refund a partial application fee.
Fix webpay test failures caused by stripe changes.
Stripe: return the failing result if the refund is successful, but the application fee fails.
Use MultiResponse for issuing refunds with application fees
Add stripe unit test for refund with refund_fee_amount passed in
Remove variable assignment when passing in meta options
Add Stripe tests for unsuccessful refunds at each potential failure step
Merge pull request #786 from Shopify/stripe-partial-application-fee-refund

Stripe partial application fee refund
Added support for iPay88 integration
Swap service_url and entry_url to play nice with ActiveMerchant's payment_service_for view helper
swap entry and service url.
Ipay88 comment cleanup.
Bump for release v1.36.0
Fix argument passing in NAB gw