Added support for initWithObjectsAndKeys:

The code that re-uses the initWith implementation could be improved. For example, there's no need to loop over the arguments array, I think using Array.prototype.slice.apply(arguments, etc.) is a better approach.

Also, to class_getInstanceMethod, use the appropriate runtime function for getting the selector, rather than assuming its a string, since that may change.

Finally, I believe there is also a runtime method for directly getting the impl, rather than calling .method_imp.

Other than that, it looks good. Perhaps submit to github and send a github commit link next time. Looking forward to the patch.