Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-content/plugins/wordpress-seo-premium/classes/validation-error.php

@@ -0,0 +1,21 @@
+<?php
+/**
+ * WPSEO Premium plugin file.
+ *
+ * @package WPSEO\Premium\Classes
+ */
+
+/**
+ * Value object containing a validation error.
+ */
+class WPSEO_Validation_Error extends WPSEO_Validation_Result {
+
+	/**
+	 * Gets error as the validation result type.
+	 *
+	 * @return string
+	 */
+	public function get_type() {
+		return 'error';
+	}
+}