#359 Add question about stop rendering operation

[Alessar]

During rendering operation application shows "Cancel" button.
If in this moment user press "ESC" (Or press "Cancel" button) rendering operation stops.
It will be good if in this moment application can show simple dialog with question like "Do you really stop rendering? yes/no". I suppose it helps to prevent accidentally stops the rendering.

[Eric Raijmakers]

Thanks for the suggestion.
I can understand why this is helpful.

I'll update Vidiot to include this.

[Eric Raijmakers]

[r2702]