changed the cache extension to .php (closes #15)

git-svn-id: http://svn.twig-project.org/trunk@83 93ef8e89-cb99-4229-a87c-7fa0fa45744b

lib/Twig/Loader.php

@@ -110,7 +110,7 @@ abstract class Twig_Loader implements Twig_LoaderInterface
 
   public function getCacheFilename($name)
   {
-    return $this->cache.'/twig_'.md5($name).'.cache';
+    return $this->cache.'/twig_'.md5($name).'.php';
   }
 
   protected function compile($source, $name)