plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BC%EF%BC%83%2B%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB%E3%83%BB%E3%83%95%E3%82%A9%E3%83%AB%E3%83%80
plugin=diff is not implemented.