iTunes Radio Support

Added the same support that was previously created for Pandora Radio to iTunes Radio.  Now when pressing the "star" button on the now playing song in iTunes Radio, an option to open the current song in Spotify is presented.  Works just it does for Pandora.
![2014-01-09 18 05 09](https://f.cloud.github.com/assets/1226826/1883927/f731e4c6-7990-11e3-9693-2ba45797d07d.png)