Started messing with injecting back/forward buttons. Going to be more difficult than expected:

1. The CSS for toggle buttons is only served up by Rdio if required, which means the user has to load their collection for it to show properly (initial page does not need it).
2. The header does some ajaxy operations which seem to remove anything I inject on dom ready (or even when $('#header') element is loaded. Which means I have to listen for some other event to know when I can inject the controls... no idea what event though.
3. Need to keep track of history to not let user back out of rdio.com (initial load is rdio.com/signup which redirects to rdio.com if user is signed in)

Current revision works but in a very buggy and unreliable way.