Added a license and formatted the README file

There should be a license for the site and its source code so I added the GPL v3.

(Honestly, I'm not 100% sure that the GPL is the best one to use, but at least if we start off with the GPL, downgrading to something more permissive in the future is always a possibility. The reason I think the GPL is a fair choice is because it prevents derivatives from being "closed". What still remains to be checked out is that all the licenses used by the various dependancies are compatible with the GPL. I know that ZendFramework uses the BSD, and most of the others use the MIT - I think those are fine but I'm not sure.)

Also, I'm not sure as to the requirements to run the project, but we should have them listed somewhere. I added a few more to the README file and changed the formatting/wording.