sytzeloor/elfproef — pull request #3 by hjblok (2012-08-30 10:05:13+00:00)
Title: Payment reference

I've added a PaymentReferenceValidator for validating the payment reference (betalingskenmerk). I've used the validation calculations from [Specificaties van de acceptgiro](http://www.acceptgiro.nl/Downloads/Cu_RR_Ac_BijlageG_Formspecs.pdf).