plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BC%EF%BC%83%2B%E3%83%90%E3%82%A4%E3%83%8A%E3%83%AA%E3%83%BB%E3%83%86%E3%82%AD%E3%82%B9%E3%83%88%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB%E3%81%AE%E5%88%A4%E6%96%AD
plugin=diff is not implemented.