Better Organization

This pull does a little bit to help organize things and present things better.

* photos in a `photos` directory
* relative urls

This files the photos away into a `/photos` directory. This prevents the directory tree from pushing the `README` content down the page as more photos are added.

It also switches to using relative image urls so things will always render when viewed in a branch and is otherwise just more convenient.

You can see how it renders here - https://github.com/maddox/occupyhongkong/tree/organize