Interchange feature

I tried to implement the `data-interchange` directive (http://foundation.zurb.com/docs/components/interchange.html). It works pretty well, I think all the features are implemented. There's probably (even definitely) a better way to code it and test it.
Tell me what you think about it.
Thanks
@maxwellito Why do we require the attribute to be `data-interchange`? Seems to work just fine without the `data` prefix.