JSONKit.m のエラーを修正
参考URL
https://github.com/jrmiddle/JSONKit/commit/ccc0565f0ae4a27371d18309ccb982a9f1f21b63
http://wiki.ad-stir.com/ARC%E3%82%A2%E3%83%97%E3%83%AA%E3%81%AB%E7%B5%84%E3%81%BF%E8%BE%BC%E3%82%80