make processPaymentRequest() use a single SendCoinsRecipient

- as one this pulls main purpose is to change a payment request to
  be displayed as a single sendcoins entry

src/qt/paymentserver.h

@@ -109,7 +109,7 @@ private slots:
 
 private:
     static bool readPaymentRequest(const QString& filename, PaymentRequestPlus& request);
-    bool processPaymentRequest(PaymentRequestPlus& request, QList<SendCoinsRecipient>& recipients);
+    bool processPaymentRequest(PaymentRequestPlus& request, SendCoinsRecipient& recipient);
     void handleURIOrFile(const QString& s);
     void fetchRequest(const QUrl& url);