Add braintree gateway support for custom processor id's.
Added support for USA ePay's Advanced SOAP interface.

Refactored UsaEpayGateway to delegate to UsaEpayTransactionGateway
or UsaEpayAdvancedGateay based on given credentials.
Expired cards should have only one error on year.

Previously, an expired card would have two errors, "expired" and "is
not valid year". But the second error is redundant and less
precise. This commit adds a clause to prevent the "is not valid year"
error from being added if the card is simply just expired.
Elevon.rb - Added Test/Demo URL
Modify create_customer_profile_request to support the validation_mode option
Updated service_url to the canonical 2Checkout purchase URL
Payment response now includes eWayTrxnNumber
Braintree: handle gateway_rejected transactions gracefully
Adding the WEB echeck_type to authorize.net CIM.
Changed Protx to SagePay in the Readme
Dwolla: Fix fields being submitted

closes #202
Dwolla: Make sure @raw is set when parse is called
Merge pull request #199 from jamesalmond/patch-1

Changed Protx to SagePay in the Readme
Merge pull request #189 from vampirechicken/master

Updated service URL
Merge pull request #180 from castiglione/error-for-expired-year

Expired cards should have only one error on year.
Merge pull request #185 from kylekeesling/master

Added test URL for Elavon/MyVirtualMerchant Gateway
Require the version file relatively in the gemspec

Avoids double require of the version file.
changes requested by jduff
Payflow Link: Use secure token for passing data to PayPal
Add refund method to some gateways that do referenced credits