Install Node.js, NPM, Bower & Grunt CLI using the Node cookbook

Installs Node & NPM from source, using Git to clone the repo
Set platform for ChefSpec tests, refactor tests for included recipes
Ensure ChefSpec tests for appropriate group ownership
Ensure Git is installed, for use by Capistrano deployments
Add ServerSpec tests for additional components

Git is needed for Capistrano deployments
Bower & Grunt are needed for builds, and Node/NPM are needed to install
them