Use auto-synthesize

Mobile Buy SDK/Mobile Buy SDK/Models/BUYCheckout.m

@@ -160,7 +160,7 @@
 	self.updatedAtDate = [dateFormatter dateFromString:dictionary[@"updated_at"]];
 	self.creditCard = [BUYMaskedCreditCard convertObject:dictionary[@"credit_card"]];
 	self.customerId = [dictionary[@"customer_id"] copy];
-	self.note = [dictionary[@"note"] copy];
+	self.note = dictionary[@"note"];
 	
 	self.privacyPolicyURL = [NSURL buy_urlWithString:dictionary[@"privacy_policy_url"]];
 	self.refundPolicyURL = [NSURL buy_urlWithString:dictionary[@"refund_policy_url"]];