Add upstream plugins

Signed-off-by: Adrian Nöthlich <git@promasu.tech>

wp-content/plugins/all-in-one-event-calendar/vendor/twig/Node/Expression.php

@@ -0,0 +1,20 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) 2009 Fabien Potencier
+ * (c) 2009 Armin Ronacher
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Abstract class for all nodes that represents an expression.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+abstract class Twig_Node_Expression extends Twig_Node
+{
+}