title: Compiler Error with LLVM 5.1 "Deprecated isa"
body: <p>I am getting compiler errors with <code>libJSONKit</code> and in <code>JSONKit.m</code>. 
  The errors are thrown with this: <code>"Assignment to Objective-C's isa is deprecated in favor of object_setClass()"</code>.<br>
  There is also a secondary error:
        <code>"Direct access to Objective-C's isa is deprecated in favor of object_getClass()".</code></p>
  
  <p>Any advice on workarounds or solutions?</p>