Use PaymentCard instead of CreditCard

- Fixed deprecation messages.
- Fixes #639.
- Fixes #648.
- Updated Samples.

sample/payments/AuthorizePayment.php

@@ -8,10 +8,10 @@ require __DIR__ . '/../bootstrap.php';
 
 use PayPal\Api\Address;
 use PayPal\Api\Amount;
-use PayPal\Api\CreditCard;
 use PayPal\Api\FundingInstrument;
 use PayPal\Api\Payer;
 use PayPal\Api\Payment;
+use PayPal\Api\PaymentCard;
 use PayPal\Api\Transaction;
 
 // The biggest difference between creating a payment, and authorizing a payment is to set the intent of payment
@@ -25,8 +25,8 @@ $addr->setLine1("3909 Witmer Road")
     ->setCountryCode("US")
     ->setPhone("716-298-1822");
 
-$card = new CreditCard();
-$card->setType("visa")
+$paymentCard = new PaymentCard();
+$paymentCard->setType("visa")
     ->setNumber("4417119669820331")
     ->setExpireMonth("11")
     ->setExpireYear("2019")
@@ -36,7 +36,7 @@ $card->setType("visa")
     ->setBillingAddress($addr);
 
 $fi = new FundingInstrument();
-$fi->setCreditCard($card);
+$fi->setPaymentCard($paymentCard);
 
 $payer = new Payer();
 $payer->setPaymentMethod("credit_card")