Update Twig from 1.35.0 to 1.42.4 (PHP 5.5 is now required!)

This fixes some errors on PHP 7.4 and contains even more fixes
Also bumped PHP version to 5.5 as Twig requires it.

system/libs/Twig/Twig/NodeInterface.php

@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Twig\Compiler;
+
+/**
+ * Represents a node in the AST.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @deprecated since 1.12 (to be removed in 3.0)
+ */
+interface Twig_NodeInterface extends \Countable, \IteratorAggregate
+{
+    /**
+     * Compiles the node to PHP.
+     */
+    public function compile(Compiler $compiler);
+
+    /**
+     * @deprecated since 1.27 (to be removed in 2.0)
+     */
+    public function getLine();
+
+    public function getNodeTag();
+}