isolationMode improvements

`test isolationMode` demonstrate de problem with the isolation. 

Solutions:

* We can support multiple modes, including a mode where a deep clone is used. I think this will be useful as well.

* Implement a heirDeep as described in this gist: https://gist.github.com/4596751, which takes care of the deep prototypal inheritance and should be considerable faster than clone and minimal footprint since it only create empty objects to inherit from every objects in the tree.