⌂ Affecting items only on the left or rigth of a linebreak (BarLines, KeySignatures, Clefs etc)

If you want to affect the behaviour (color, rotation, translate etc.) of an item at a linebreak only on the left or the right side (like BarLines, KeySignatures, Clefs, TimeSignatures etc.) use the definitions and functions as defined here. Several other definitions are possible by using this examples.