Removed API-specific default values from gateway class (temporary).

All the default values in the gateway class *must* be supported with
setters and getters in all request messages that the gateway supports;
the core tests insist on this. Most of those parameters are irrelevant
for the complete*, the acceptNotification and the other backend functions,
so make no sense to implemement. Those messages will probably have to be
moved to a "Backend" gateway class so the default parameters match the
supported message parameters.

README.md

@@ -122,14 +122,16 @@ $request = $gateway->purchase([
     ...normal purchase data (TODO: examples)...
     ...additional gateway-specific feature data (TODO: examples)...
     //
-    // These three URLs are mandatory to the gateway, but will be defaulted to the
+    // These three URLs are required to the gateway, but will be defaulted to the
     // returnUrl where they are not set.
     'returnUrl' => 'https://example.com/complete',
     //'cancelUrl' => 'https://example.com/complete?status=cancel', // User cancelled
     //'failureUrl' => 'https://example.com/complete?status=failure', // Failed to authorise
     //
+    // These two URLs are required.
     'notifyUrl' => 'https://example.com/acceptNotification',
     'serviceUrl' => 'https://example.com/terms_of_service_and_contact',
+    //
     'confirmMail' => '[email protected]',
 ]);
 $response = $request->send();

src/CheckoutPageGateway.php

@@ -36,19 +36,23 @@ public function getDefaultParameters()
         // Parameters for Checkout Page and Checkout Seamless APIs.
         // TODO: move these to an AbstractCheckoutGateway class once
         // Seamless is supported.
+        /*
         $params['noScriptInfoUrl'] = '';
         $params['windowName'] = '';
         $params['duplicateRequestCheck'] = true;
         $params['transactionIdentifier'] = '';
         $params['financialInstitution'] = '';
         $params['cssUrl'] = '';
+        */
 
         // Parameters specific to Checkout Page API.
+        /*
         $params['displayText'] = '';
         $params['imageUrl'] = '';
         $params['backgroundColor'] = '';
         $params['maxRetries'] = null;
         $params['paymenttypeSortOrder'] = '';
+        */
 
         return $params;
     }