resolves #117: you can no longer add settings if the last one is a Hold, and a warning will be issued to the user
resolves #117: you can no longer add settings if the last one is a Hold, and a warning will be issued to the user

jimrybarski/piwarmer,jimrybarski/piwarmer,jimrybarski/raspberrypid,jimrybarski/piwarmer,jimrybarski/raspberrypid,jimrybarski/raspberrypid