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/Loader/ArrayLoader.php

@@ -0,0 +1,102 @@
+<?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.
+ */
+
+namespace Twig\Loader;
+
+use Twig\Error\LoaderError;
+use Twig\Source;
+
+/**
+ * Loads a template from an array.
+ *
+ * When using this loader with a cache mechanism, you should know that a new cache
+ * key is generated each time a template content "changes" (the cache key being the
+ * source code of the template). If you don't want to see your cache grows out of
+ * control, you need to take care of clearing the old cache file by yourself.
+ *
+ * This loader should only be used for unit testing.
+ *
+ * @final
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ArrayLoader implements LoaderInterface, ExistsLoaderInterface, SourceContextLoaderInterface
+{
+    protected $templates = [];
+
+    /**
+     * @param array $templates An array of templates (keys are the names, and values are the source code)
+     */
+    public function __construct(array $templates = [])
+    {
+        $this->templates = $templates;
+    }
+
+    /**
+     * Adds or overrides a template.
+     *
+     * @param string $name     The template name
+     * @param string $template The template source
+     */
+    public function setTemplate($name, $template)
+    {
+        $this->templates[(string) $name] = $template;
+    }
+
+    public function getSource($name)
+    {
+        @trigger_error(sprintf('Calling "getSource" on "%s" is deprecated since 1.27. Use getSourceContext() instead.', \get_class($this)), E_USER_DEPRECATED);
+
+        $name = (string) $name;
+        if (!isset($this->templates[$name])) {
+            throw new LoaderError(sprintf('Template "%s" is not defined.', $name));
+        }
+
+        return $this->templates[$name];
+    }
+
+    public function getSourceContext($name)
+    {
+        $name = (string) $name;
+        if (!isset($this->templates[$name])) {
+            throw new LoaderError(sprintf('Template "%s" is not defined.', $name));
+        }
+
+        return new Source($this->templates[$name], $name);
+    }
+
+    public function exists($name)
+    {
+        return isset($this->templates[(string) $name]);
+    }
+
+    public function getCacheKey($name)
+    {
+        $name = (string) $name;
+        if (!isset($this->templates[$name])) {
+            throw new LoaderError(sprintf('Template "%s" is not defined.', $name));
+        }
+
+        return $name.':'.$this->templates[$name];
+    }
+
+    public function isFresh($name, $time)
+    {
+        $name = (string) $name;
+        if (!isset($this->templates[$name])) {
+            throw new LoaderError(sprintf('Template "%s" is not defined.', $name));
+        }
+
+        return true;
+    }
+}
+
+class_alias('Twig\Loader\ArrayLoader', 'Twig_Loader_Array');