PHP Proxy

This is a web proxy that applies several transformations to the request and response in order to:

1. Rewrite all links to forward to the proxy URL
2. Rewrite all asset URLs, including images in CSS files
3. Inject a header form to allow easy navigation
4. Obfuscate the page content, and de-obfuscate in JavaScript on the client
5. Correctly handle cookies to isolate them between requests - including document.cookie support
6. Forward post request data