[DONE] Focus stacking: honor 10/2 sec delay

[Marsu42]

When starting a focus stack via the menu it starts instantly, but it'd be important that there is a 2/10 sec timer delay because when putting the camera on a not-so-sturdy tripod or something else improvised (no choice at ground level) it needs some swing-in time - otherwise the first couple of shots are broken.

* Suggestion: Simply add a 2/10s delay if the self-timer was set before starting the stack.