Update PayPal.class.php

Updated the version number to the most recent one
Added shipping prices
Added Turkish currency support (not available in sandbox environment)
Added landing page and solution type parameters (For more info, please read the PayPal NVP documentation)
Changed the card item array storing method because of some setbacks caused by products with same names
Added a new method called addShipping
Added PAYMENTREQUEST_0_SHIPPINGAMT to the order details