Update hashbang in entry script
Update composer dependencies
Update to use ReactPHP for the server command

Now creates a server and runs the "runner". Also stops using
environmental variables in favor of a cement.json file in the repo root.
Add sample cement.json file
Add limited HTML capabilities to server

The cement server will now respond with an HTML response detailing the
status of the last build. This is achieved through Twig templates.
Add LICENSE to project