Remove optimization that was causing crash on 64-bit

@confucious - review

Apparently JSON Kit was relying on a hacky way to obtain the class of an object, that doesn't work on 64 bit architectures. The comment describes what it was, and when removed the app seems to work fine. In theory this could hit performance but I didn't see any significant change. We could potentially disable the optimization only for 64 bit architectures, but I think it's better to just get rid of it since it doesn't seem to be saving A LOT of time, and it will probably cause problems in the future.

I still think it would be good to remove JSONKit, but this should work for now.