Add Github-pages flavor

#21 

1. Re-create your ``install.sh`` from ``default.install.sh``, and make sure to delete ``dekyll/libraries/composer.lock``
2. Install Dekyll, and I'll let you figure it out from there

* Note that we still don't implement fancy JS to re-load your page once the repo was cloned, so it's up to you to hit the F5.
* The Github App is assuming you have Dekyll installed on ``http://localhost/dekyll/www`` -- if that' not the case, you can create your own Github app.