Pointless !.
Not needed.
Renamed YouTubeDlJob to YouTubeJob.
Updated string that is going to fit with the youtube-dl checker.
Started work on YouTubeChecker.

It is going to check if youtube-dl is installed.
Renamed signal jobYouTubeDlFinished to jobYouTubeFinished.
Missing #include.
Wire up the youtube checker with the job pool.
Renamed jobCheckerFinished to jobMP4BoxCheckerFinished.
Put the settings in a scroller.
Checking for youtube-dl in the settings dialog.
Remve new lines from the version string.
Spacer label.

I'm sure there is a better way, but this just works.
Load youtube-dl location from settings in the checker.
youtube-dl checking in the youtube-dl dialog.
Ignore aborted jobs.
Renamed isStopping() to stopped().
Those <zorder> tags only caused warnings.

Removing them doesn't break the layout.
Actually give external procs time to terminate.