Thumbs up/down images are incorrect

[kbhomes]

On a very related note, maybe figure out some way to make these styles more robust. Seems that Google's spritesheet generating mechanism regularly creates different spritesheets that relocate the thumbs up and down icons. Therefore we should try to figure out a way to move the thumbs up and down in each .song-row without changing the background-position.

Alternatively, we can have the app download and use the latest version of the stylesheet every time the application runs so that simple style changes can be pushed to everybody without requiring an update of the app every time. Alternatively, we could include a built-in style manager (tangentially, user provided styles, perhaps...?) that downloads the latest style, but that could be confusing as it creates two points of update for the user, the stylesheets and the app itself.