Now npm ready

Hey,

I was looking over this code and was worried that the only way to install it was to hard link the path into a require. Like:

`var ping = require('./lib/ping.js');`

With the updates in this pull users should be able to npm install the module and include it in their app as per all other npm modules.

A few other minor tweaks were made, including:

* Build file
* Update readme
* Update package.json (most importantly it now points to your current GitHub)

Let me know what you think.