Control of the autosave requires better UX

QDS should have autosave on by default now, if the user does rapid iteration and does not choose 'always save' on the first go, he/she is presented with many save dialogs needlessly.

Each time QML file is updated with visual editor, DS marks it 'dirty' and won't run the player until the changes are done. Enabling and disabling autosave should be easier. The current dialog with 5 buttons is not good UX.