fixed optimizer max value

CHANGELOG

@@ -1,5 +1,6 @@
 * 1.15.0 (2013-XX-XX)
 
+ * fixed a bug that prevented the optimizers to be enabled/disabled selectively
  * fixed first and last filters for UTF-8 strings
  * added a source function to include the content of a template without rendering it
  * fixed the C extension sandbox behavior when get or set is prepend to method name

lib/Twig/NodeVisitor/Optimizer.php

@@ -39,7 +39,7 @@ class Twig_NodeVisitor_Optimizer implements Twig_NodeVisitorInterface
      */
     public function __construct($optimizers = -1)
     {
-        if (!is_int($optimizers) || $optimizers > 2) {
+        if (!is_int($optimizers) || $optimizers > (self::OPTIMIZE_FOR | self::OPTIMIZE_RAW_FILTER | self::OPTIMIZE_VAR_ACCESS)) {
             throw new InvalidArgumentException(sprintf('Optimizer mode "%s" is not valid.', $optimizers));
         }