fix Issue 12409 - Add "each" function as found in Ruby and jQuery

https://d.puremagic.com/issues/show_bug.cgi?id=12409
It's more than that, http://en.wikipedia.org/wiki/Functional_predicate but in any case we should use terms correctly and consistently:
1. such will suggest to the knowledgeable user that we know what we're doing
2. such will give confidence to the newbie that he understands what the code does