plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BC%EF%BC%83%2B%E5%87%A6%E7%90%86%E6%99%82%E9%96%93%E3%82%92%E6%AD%A3%E7%A2%BA%E3%81%AB%E8%A8%88%E6%B8%AC%E3%81%99%E3%82%8B%E6%96%B9%E6%B3%95
plugin=diff is not implemented.