let's add awesome feature:clone the entire engine,or save and resume

[新买]

In the old rhino engine, there is a powerful feature: Continuation,
Continuation give a chance to save the entire engine, and can store into
file,db or other persistence.

Rhino: Ability to pause, save state and resume javascript - Stack Overflow
http://stackoverflow.com/questions/25837444/rhino-ability-to-pause-save-state-and-resume-javascript

in my solution, i want a lot's of nashorn engines running and store and
awake from disk. and clone engine is a best way to avoid run the initialize
script on each nashorn engine.

Hope you accept this amazing suggestion ^_^

Best Regards