some error in XCode 4.6

[zwx17603]

JSONKit.m:663:12: Direct access to objective-c's isa is deprecated in favor of object_setClass() and object_getClass()

array->isa = _JKArrayClass;

[Jarada]

For now replace:

array->isa = _JKArrayClass;

With:

object_setClass(array, _JKArrayClass);

And:

dictionary->isa = _JKDictionaryClass;

With:

object_setClass(dictionary, _JKDictionaryClass);