1. Added .gitignore
2. Added namespaces
3. Added currency constants
4. Removed individualized parameter properties
5. Wrapping functionality of _getSignInData() with try...catch, because
failure in Zend_Config_Ini will result in Zend_Config_Exception being
thrown
6. Added specialized parameter key paymenttoken to datacash payment-gateway
7. Created Payment_Gateway_Gateway for unit-testing (you can't instantiate
an abstract class)
8. Started unit-testing Payment_Gateway_Gateway()