Enabled Payment Experience

- Updated Api to enabled Payment Experience
- Updated Tests and Samples
- Added Json Validator
- Ability for PPModel to return array of self objects

sample/payment-experience/ListWebProfiles.php

@@ -0,0 +1,28 @@
+<?php
+
+$apiContext = require __DIR__ . '/../bootstrap.php';
+
+// ### Retrieve List of All Web Profiles
+// Documentation available at https://developer.paypal.com/webapps/developer/docs/api/#list-web-experience-profiles
+
+// Retrieve the list of all web profiles by calling the
+// static `get_list` method on the WebProfile class.
+// (See bootstrap.php for more on `ApiContext`)
+try {
+    $list = \PayPal\Api\WebProfile::get_list($apiContext);
+} catch (\Exception $ex) {
+    echo "Exception: " . $ex->getMessage() . PHP_EOL;
+    if (is_a($ex, '\PayPal\Exception\PPConnectionException')) {
+        /** @var $ex \PayPal\Exception\PPConnectionException */
+        var_dump($ex->getData());
+    }
+    exit(1);
+}
+$result = '';
+foreach ($list as $object) {
+    $result .= $object->toJSON(JSON_PRETTY_PRINT) . PHP_EOL;
+}
+
+print_result("Get List of All Web Profiles", "Web Profiles", null, $result);
+
+return $list;