In #293 / #291, I changed protocols to work like traits.

However, NSCopying and NSMutableCopying are still special-cased since they work a bit differently, they require the user to specify the output type and ownership. How can we make icrate do that for us? And what about protocols that "inherit" from these two (like DOMEventTarget)?

Perhaps this ties in with #399 somewhat?

In any case, I need to get a better understanding and research which types actually implement these two protocols, and just as importantly, which ones don't!