UMD Wrapping for Javascript and package.json

Employed a simple UMD wrapper for `rison.js` making it loadable using AMD, CommonJS (browserify, node), or includable using a `<script src="js/rison.js"></script>` tag.

I also took the liberty of creating a `package.json` file and publishing the module to NPM.
If you're interested I would love to add you as owner of the npm package, just drop me your NPM username :)

Btw, the example page is down, perhaps we should make a static one and host it on github pages, so it won't go away...