avoid creating unused results arrays

[timruffles]

iterators in Coffeescript will create result arrays (check JS source to see them) if they're the last expression in a function. added return nulls here to avoid them

[chenglou]

What a coincidence, I was just thinking about that! Thanks a lot.
I have the habit of keeping things constant and use undefined instead for everything that has the null concept. How about just return?

[timruffles]

good point, even clearer!

[chenglou]

I just updated everywhere that unnecessarily returns an accumulated array, commented on them, repacked and updated the wiki. You can get the new version now and I'll close this pull. Thanks for the suggestion!