Initial release

This is a initial proof of concept that will download a URL, assume it is HTML, run it through Beautiful Soup and process every <link>, <script>, and <img> to either include external resources (CSS and JS) or turn them into a data: URL. It also further processes CSS to turn url(...) into url(data:...).

This pulls in everything, without timeouts, and fails hard if anything doesn't work as expected. There is a bunch of basic functionality that should be implemented before this is used for anything other than playing around.