Enabled EC Parameters support

- Updated Api to enabled EC Parameters
- Updated Tests
- Updated Logging Manager
- Added a feature to do validation on accessors.

lib/PayPal/Validation/UrlValidator.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace PayPal\Validation;
+
+/**
+ * Class UrlValidator
+ *
+ * @package PayPal\Validation
+ */
+class UrlValidator
+{
+
+    /**
+     * Helper method for validating URLs that will be used by this API in any requests.
+     *
+     * @param      $url
+     * @param string|null $urlName
+     * @throws \InvalidArgumentException
+     */
+    public static function validate($url, $urlName = null)
+    {
+        if (filter_var($url, FILTER_VALIDATE_URL) === false) {
+            throw new \InvalidArgumentException("$urlName is not a fully qualified URL");
+        }
+    }
+}