Create SEPA files for Direct Debit

Module to export direct debit payment orders in SEPA XML file format.

SEPA PAIN (PAyment INitiation) is the new european standard for
Customer-to-Bank payment instructions. This module implements SEPA Direct
Debit (SDD), more specifically PAIN versions 008.001.02, 008.001.03 and
008.001.04. It is part of the ISO 20022 standard, available on
http://www.iso20022.org.

The Implementation Guidelines for SEPA Direct Debit published by the European
Payments Council (http://http://www.europeanpaymentscouncil.eu) use PAIN
version 008.001.02. So if you don't know which version your bank supports, you
should try version 008.001.02 first.
