Make output for JS values interactive

At the moment output for JS values is pretty much useless, what we should render instead is something
similar to web inspector's objects that can be navigated or folded. Also ideally folding should be preserved between edits and fields updated. Regardless of weather identity of the value is same or not.

Probably we need something like a `render` function that takes previous state and current state and returns a DOM node back that is then injected into output.