Restore 2.5 compat by activating with_statement future

youtube_dl/__init__.py

@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
+from __future__ import with_statement
+
 __authors__  = (
 	'Ricardo Garcia Gonzalez',
 	'Danny Colligan',