change the notification success parameter to match other gateways
add the end
adjust payfast parameter name to match output
add a stub for currency return
move test? and currency into the base notification object
Merge pull request #495 from Shopify/notification_name_test

final bug fixes for payfast integration
fix payfast notification tests
remove default nil currency from the base notification class, and define it manually in the child class
Merge pull request #497 from Shopify/notification_name_test

Fixed payfast tests
Merge pull request #492 from Shopify/update-iridium-card-types

Update supported cards for the Iridium gateway
Make 0000 default post code for everyone if missing
Update test name
Add A1Agregator integration

http://a1agregator.ru/

Closes #468.
Merge pull request #471 from npverni/stripe_add_canada_to_supported_countries

Stripe gateway: Add Canada as a supported country
Refactor Gateway#test? and assignment of @options

Up till now, we've depended on each gateway defining a sane #test?
method, which ended up with almost every gateway having the exact same
definition of #test?. This commit pulls that common definition up to the
Gateway class.

As part of doing this, since the definition of #test? is dependent on
@options, I had to also pull up `@options = options` to
Gateway#initialize, which also eliminated a ton of duplication between
gateways.

This should be a strict refactoring - no functionality or external APIs
should be affected.

Closes #408.
Realex gateway: Fix billing address format

Probably due to a misreading of the Realex docs, the billing address
was being passed in a manner that's only appropriate for the Realex
offsite/integration method, not the direct API. This simply matches
handling of the billing address up with how the shipping address was
already handled, and tweaks the test to reflect that change.

Closes #479.
Orbital gateway: handle custom AVS response codes

Orbital has their own custom set of AVS response codes. This introduces
a custom AVS class for Orbital that translates those codes into what
ActiveMerchant expects.

Also required some refactoring of Billing::Response to allow a custom
AVS response class to be used. Which, in turn, required some fixes in
the BluePay gateway.

Closes #465.
Orbital gateway: Fix infinite connection retry

Orbital could very easily land in an infinite retry situation if unable
to connect. In general retry should be a concern external to
ActiveMerchant, but in the Orbital case there is a secondary url that
should be tried before giving up. This removes generalized retries, but
retains a single retry at the secondary url.

Closes #464.
Paypal integration: Add support for MassPay IPN

MassPay can have multiple transactions batched up into one MassPay
payment. When the IPN notification is sent it contains details for all
the individual transactions in the one notification.

Closes #486.
Orbital gateway: Fix status of void result

The success? method in the Orbital Gateway wasn't correct for the case
of a void. Even if void was successful, it was marking it as a failed
response.

Closes #482.