added Chorus strategy

added a strategy to support [Chorus](https://github.com/jez500/chorus), a super-nice web UI for XBMC/Kodi.

Controls XBMC or local playback depending on which you have active in your browser.
Actually, you could probably use a more specific regex.  When it initializes, the document title is "Chorus."  Then after that it'll either be "▶ Nothing Playing | Chorus." or "▶ [Song Title] | Chorus."