MDL-55285 core: Include library scssphp in core

Part of MDL-55071

lib/scssphp/Exception/ParserException.php

@@ -0,0 +1,21 @@
+<?php
+/**
+ * SCSSPHP
+ *
+ * @copyright 2012-2015 Leaf Corcoran
+ *
+ * @license http://opensource.org/licenses/MIT MIT
+ *
+ * @link http://leafo.github.io/scssphp
+ */
+
+namespace Leafo\ScssPhp\Exception;
+
+/**
+ * Parser Exception
+ *
+ * @author Oleksandr Savchenko <[email protected]>
+ */
+class ParserException extends \Exception
+{
+}