JavaScript port of TextStatistics.php!

I've done what I think is a reasonably faithful port. Documentation incoming! I removed a lot of the original comments during the port, but seeing as the API remained largely the same, I'll add them in shortly.

The beginning of a test suite in Mocha is here, covering cleaning the text and some cases of word and sentence counting.

Run this in the browser using a simple <script> include - or you can install for node with npm install text-statistics.

Famous! As seen in Time! (heh.)