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/ArgumentValidator.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace PayPal\Validation;
+
+/**
+ * Class ArgumentValidator
+ *
+ * @package PayPal\Validation
+ */
+class ArgumentValidator
+{
+
+    /**
+     * Helper method for validating an argument that will be used by this API in any requests.
+     *
+     * @param $argument     mixed The object to be validated
+     * @param $argumentName string|null The name of the argument.
+     *                      This will be placed in the exception message for easy reference
+     */
+    public static function validate($argument, $argumentName = null)
+    {
+        if (
+            $argument != null &&
+            (
+                (gettype($argument) == 'string' && $argument == '')
+                ||
+                is_array($argument) && empty($argument)
+            )
+        ) {
+            //Throw an Exception for string or array
+            throw new \InvalidArgumentException("$argumentName cannot be null or empty");
+        } elseif ($argument == null) {
+            //Generic Exception
+            throw new \InvalidArgumentException("$argumentName cannot be null");
+        }
+    }
+}