Added Node.js web server for easier local testing.

Because modern web browsers won't allow Javascript that's on the local machine to be executed, a web server is required to run a copy cloned to the local machine. This usually involves installing and configuring something like apache or nginx.

As Node.js is increasingly being used for web development tools, there's a likelihood that Node.js will be installed on the system. In this case, we can use a web server written in Node.js like the one in this pull request.