Added Vagrant support

I've added Vagrant support. Vagrant it's an automatization tool that will create a new virtual machine fully configured for algebra development (it will create an Ubuntu VM and install grunt+browserify+all dependencies with only one command) making it very very easy for other people to contribute. I've also improved the current documentation (Development.md) describing the full process to setup an algebra dev environment using Vagrant.

All the main job is done within the vagrantfile. Node/NPM are set up inside the VM using Chef. Grunt, Browserify and all other dependencies are executed via shell.