Support accessing parent scope within an iterator

[aghouseh]

Is this a shortcoming that anyone else has discovered with the CF implementation?

http://jsfiddle.net/ZG4zd/20/ (found via StackOverflow)

This lib does not reach up the chain into the parent scope and beyond; it's my belief that feature is required to maintain spec compliance with Mustache.

Has anyone else run into this that has a solution? I'd love to explore some ideas around it, even if it not deemed valid for this repo.