Feature request: Add indicator whether current changes are saved

[stefandesu]

I noticed that changes are saved to the server on an interval, not on every change. That means that if I change something and close the page before the next save, the changes are lost. It would be nice to have an indicator whether the current changes are saved. This would also be helpful if there's currently no connection to the server (then I could keep the page open until connection is back so that changes are transferred.)

(Although to be honest, I think it would be even better if every change would be saved to the server immediately if possible. Or changes could be saved to local storage and flushed to the server on an interval, meaning that they don't get lost if I close the page before they are saved to the server.)