Option to disable processing of tracks with no master/parent send or other sends

When a track is muted you can disable that track from processing, saving CPU power. Similarly, it would make sense to have an option to not process a track with no master/parent sends, or any other sends (therefore effectively muted).

This most commonly comes into effect when 'freezing' folder tracks -- the child tracks inside the folder will have their master/parent send disabled, because their audio has been lumped and frozen with their parent folder, but still use up processing power, requiring the additional steps of muting them, and then un-muting them when unfreezing their parent folder track, to get the desired effect of freeing up processing power from freezing a folder.