Add AUTHORS file
Add AUTHORS file

Thanks to
https://github.com/django-oscar/django-oscar/wiki/Releasing#contributors

st8st8/django-oscar-paypal,django-oscar/django-oscar-paypal,lpakula/django-oscar-paypal,lpakula/django-oscar-paypal,st8st8/django-oscar-paypal,evonove/django-oscar-paypal,evonove/django-oscar-paypal,lpakula/django-oscar-paypal,django-oscar/django-oscar-paypal,evonove/django-oscar-paypal,django-oscar/django-oscar-paypal,st8st8/django-oscar-paypal