Expect more naive tokenization in the wordcount problem

I checked out [the tutorial this problem was taken from](http://tour.golang.org/#43), and they do simple tokenization with no special handling of case or punctuation. I think this is the more natural way of doing it. 

(The problem with trying to strip punctuation is that holy cow language is complicated. Ideally you would remove the period from "complicated." at the end of that sentence, but aren't the apostrophes in "'tis" or "bitchin'" or "isn't" parts of those words? And then there are unicode combining characters...)

If this looks okay, I'm happy to make the same change for other languages.