*****  TODO  *****
 - ensure remote control behavior
 - check level when adding song to add-to playlist - needed?
 - enhance song widget column title - songs from artist/band directory foo ; songs from artist/band playlist foo.m3u etc. - might need Text as a TableWidgetItem
 - editing playlist widget too small - save/restore size or maximize anyhow
 - call sessionLastReCreate when root dir changed via settings dialog and same dir?


*****  fix me
 - songs widget: the suffix column is not centered when shrinking?
 - re-nameing playing playlist can be done via setting it to add-to playlist and change the name there, but the play playlist context menu does not allow re-nameing the play playlist! Change?
 - confirmation message box, e. g. about successful editing, pops up on wrong monitor
 - mpv is called 3 times per double click on a song in the table widget - why? fix this! However, qprocess is protected to allow only 1 running instance. Hint: not when playing next song automatically, only when clicking on song (single/double-click?)


*****  possible features
 - apply settings font size
 - apply settings font type
 - volume adjustment in the playlists - via master channel control
