Shopify/active_merchant — pull request #314 by dscataglini (2012-03-21 19:32:20+00:00)
Title: increased support for Paypal APIs

I added support for the following api calls

DoReferenceTransaction
ManagePendingTransactionStatus
DoAuthorization
TransactionSearch
GetBalance

Also standardized the PaymentDetails elements. There were at least 3 different version with different capabilities.
Added ExpressCheckout specific optional fields.
Removed hardcoded text for ButtonSource & NotifyUrl