Added LocalStorageBox for watching info and clearing local storage.
Local passcode and cloud password state display and editing done.
Temporary download location clearing link added.
Crash fixed in local storage clear + app close, now waiting for the
clearing thread to quit. Some design improvements and testing.
Now the background of boxes is separated to another widget.
This will allow to use a special layer widget (like settings)
together with the usual layers-boxes upon it, moving the special
widget behind the dark background when a usual layer-box is shown.
