Unwrap linkable objects passed back to parent

[danfinlay]

When a linkable object (function or object) is Proxied over capnode, and then the proxy is passed back to its parent by some method, it should be "unwrapped" to the original referenced object (vs wrapping the wrapped).

http://blog.ezyang.com/2013/03/what-is-a-membran/

Since objects can be mutated client-side, so we might need to detect changes in them, or we can just say capnode proxies are not truly mutable, only superfically locally.

[danfinlay]

A true test of object unwrapping: Can I pass my dom’s createElement along with another element reference, such that you can create new elements and append them to your permitted element?

Brings to light how properties are all synchronous but could be spoofed with getter/setter decorator functions which could trigger and reflect async updates.

That may be too hacky, but at least createElement and appendChild could be done with async-ified wrappers.

[danfinlay]

I've added a test for this on a branch.