New build that (tentatively) support Firefox for Android

- If a website publishes feeds through <link>, the extension will now show the icon in the URL bar
- Support for Atom feeds

- Better intercepted RSS feeds: the extension infers from the response headers whether the browser is trying to render a feed, and forwards it to the internal viewer.

- Fixed Firefox bug that prevented the listener from being able to parse RSS feed <link> items on an HTML page.