Updates for Google Play

[simon-weber]

Google Music is now Google Play Music, but the change seems mostly cosmetic from the api's end. All tests pass right now, but there's no guarantee they'll stay this way. Things should be looked in to:

• urls: web client calls now hit play.google.com/music/services
• markup:getting playlist ids depends on markup formatting assumptions - it seems this didn't change
• name: will people be searching for a "google play music" api now? GitHub and RTD don't get ranked for that search right now.