Samples for All Invoice Operations including QR Code

- Invoice search method is static now
- Shipping Info has proper Phone Params
- Small Changes to Image Class
- Updated Sample Docs

sample/invoice/DeleteInvoice.php

@@ -0,0 +1,27 @@
+<?php
+
+// # Delete Invoice Sample
+// This sample code demonstrate how you can delete
+// an invoice.
+
+/** @var Invoice $invoice */
+$invoice = require 'CreateInvoice.php';
+
+use PayPal\Api\Invoice;
+use PayPal\Api\CancelNotification;
+
+try {
+
+    // ### Delete Invoice
+    // Delete invoice object by calling the
+    // `delete` method
+    // on the Invoice class by passing a valid
+    // notification object
+    // (See bootstrap.php for more on `ApiContext`)
+    $deleteStatus = $invoice->delete($apiContext);
+} catch (Exception $ex) {
+    ResultPrinter::printError("Delete Invoice", "Invoice", null, $deleteStatus, $ex);
+    exit(1);
+}
+
+ResultPrinter::printResult("Delete Invoice", "Invoice", $invoice->getId(), null, null);