Setup github pages hosting and update README to reflect change

I was looking through this, and noticed that it's a static site, except for a json blob generated from `events/` and saved in `html/data/1.json`. That makes it pretty easy for this site to be hosted via [Github Pages](https://pages.github.com/)

One step I had to add was writing a script that built `html/data/1.json` and then put the `html` directory in the repo root of the `gh-pages` branch. This is accomplished by `scripts/build-gh-pages.sh` and `scripts/publish-gh-pages.sh`

With this in place it should be really easy to setup Travis to build and publish changes to the master branch like this person does: http://www.mythmon.com/posts/github-pages-travis.html

The Github Pages hosted site can be found at http://status.persona.org and once I get control of the DNS, I intent to setup http://personastatus.org to redirect there.