also need a DeepClone impl for @T and @mut T where T is Send

[thestinger]

This will conflict with the T: Freeze implementation for many types, so I don't think it's currently possible.

[emberian]

Owned => Send.

Nominating for feature complete?

[catamorphism]

Just a bug, de-nominating.

[thestinger]

This will be dealt with by the move to Gc<T>.