Added shopper_sig to Adyen::Form

Adyen offers to send shopper info to the Adyen Form flow.

Send the shopper information with the fields (at least):

    shopper.firstName
    shopper.lastName
    shopper.socialSecurityNumber (that's the CPF/CNPJ)

shopperSig: shopper.firstName + shopper.infix + shopper.lastName + shopper.gender + shopper.dateOfBirthDayOfMonth + shopper.dateOfBirthMonth + shopper.dateOfBirthYear + shopper.telephoneNumber
(Note that you can send only shopper.firstName and shopper.lastName if you like. Do NOT include shopperSocialSecurityNumber in the shopperSig!)
Added tests for shopper Adyen::Form attributes.
Merge pull request #75 from joost/patch-2

Added shopper_sig to Adyen::Form
Specify a specific RBX version
Small cleanup
Allow setting of Adyen.configuration
Append SEPA info to payment request body
Added BANK_ACCOUNT_PARTIAL in payment_service.rb template
Adding a new SEPA direct debit payment method
Added SEPA Direct Debit action
Added specs for SEPA method
Added functional specs for SEPA
Merge pull request #78 from Doppp/sepa_integration

Adding SEPA Direct Debits
Revert "Merge pull request #78 from Doppp/sepa_integration"

This reverts commit ecc863c9c05d7840a26e2846493f85b14c377f54, reversing
changes made to 2e4289356b1de9512ce31e1292dd13e18d2e05d3.