* Use require/autoload instead of const_missing
* Make sure Japansese yens work as expected (this is the only currency Adyen does not expect to be in cents)
* Ditch SOAP library dependency.
* Complete SOAP API.
* Add ActiveMerchant integration

* Split up gem to have more explicit dependency requirements, e.g.:
  * adyen-soap
  * adyen-railtie
  * adyen-activemerchant

= API