I suggest rebasing over latest master. The setting is now in the account, not in settings, so we need to get a handle on the account to determine if we need to play the sound. I appreciate there is a balance in keeping this pull request stable for review though. 

For me, I'm fine if you do the rebase soonish, since I'll want to see the result for this sound setting anyway for final review, but may be worth pinging @asuth if he is OK if you pull the rug out. I'll keep reviewing what is here for now, but just ping me if you do decide to rebase and I'll get the latest.

The rebase also has the benefit of getting the full visual refresh. It is hard for me to look at the old visual style in this pull request. My eyes, my eyes!