Firefox support, turn off key events, directory changes

This release added a Firefox extension. Aside from that it introduced the ability to disable the key listener that lets +, -, *, and / affect speed as well as enter for pause [ and ] for navigation and 'backtick' for speed reset. The folder structure is different but since the paths exist in manifest.json anyway and the entire extension folder was just moved to a subdirectory nothing was removed and nothing was broken