update twig to 2.9

inc/cache.php

@@ -186,3 +186,30 @@ class Cache {
 	}
 }
 
+class Twig_Cache_TinyboardFilesystem extends Twig\Cache\FilesystemCache
+{
+	private $directory;
+	private $options;
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function __construct($directory, $options = 0)
+	{
+		parent::__construct($directory, $options);
+
+		$this->directory = $directory;
+	}
+
+	/**
+	 * This function was removed in Twig 2.x due to developer views on the Twig library. Who says we can't keep it for ourselves though?
+	 */
+	public function clear()
+	{
+		foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator($this->directory), RecursiveIteratorIterator::LEAVES_ONLY) as $file) {
+			if ($file->isFile()) {
+				@unlink($file->getPathname());
+			}
+		}
+	}
+}