Fixed a bug in the handling of multiple charges to the same customer
SecureNet: Fix remote test
SecureNet: Cleanup

Removed unnecessary code and whacked some duplication.
SecureNet: Make interfaces more consistent

In particular, the #capture, #credit, and #void calls were inconsistent
with the other gateways in ActiveMerchant in that they took additional
parameters.  It's important for the gateways to share the same interface
and use the options hash for gateway specific stuff.

Now we use the authorization to hold the pieces SecureNet needs for
capture, credit, and void.
SecureNet: Deprecate #credit in favor of #refund

Closes #782.
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