Rewritten as a Gem, with more standard Ruby syntax and style

I've updated your Ruby library with more standard Ruby syntax

* It's now a gem (unreleased).
* Everything is rooted in the new `Pearson` module.
* Removed the monkey-patching of Hash.
* Used underscore instead of CamelCase for methods and variables.
* Corrected CamelCase for classes.

Feel free to edit as you see fit.  What license is this library?