Spotify web support, fix #104

Spotify now has a [web based](https://play.spotify.com) player but their scrobbling feature is not included.

So here my take on this.

I use a injected Javascript as the jango wrapper, because the Spotify Javascript API is quite good. All I'm doing is adding an event to their system:

    spotify_context.addEventListener("play", function () {})

And I love it :love_hotel: 

I can now enjoy my music on Linux without wine & scrobble my wonderful musical tastes, and that makes me happy.

![-J3zMlReEUy3JD0iTpTUzw2](https://f.cloud.github.com/assets/225704/10266/214894d8-4505-11e2-80dc-d8adc825a070.gif)

Cheers