Porter Stemmer

The Stemmer class transforms a word into its root form. The input word is provided from the add() methods. The stem() method will return the stem as will toString() after stem() has been
called). The clear() method will wipe the Stemmer buffer and allow a new word to be input.

This version extends Martin Porter's original stemming algorithm by allowing capital letters to exist in words. This version should also be plugged in wherever the old algorithm is used with
few accommodations necessary.

The code in this version is more readable (in my opinion) than the old version. There is a main at the bottom that shows how to use the Stemmer.