fix #20424: Impossible to delete a custom barline
fix #20541: Part not visible if created when viewing part. Rename buildin to builtin workspace
added nullpointer check in Seq::setPos(int) to avoid crash
fix #20423: Crash when deleting start repeat in the first measure
Merge pull request #277 from heuchi/10050_crash_in_pa

Fix #10050
do nothing fancy with barline and accolade when splitting staff
fix #20558: Split staff creates incorrect results
fix #10827: Clef changing
fix #20233: Pedal marks not deletable
fix #19287: Removing and adding linked staff and creating score causes crash
somes fixes in instruments.xml, fix #19019
fix #19312: Drums in 1.2 score have a treble clef after enabling Concert Pitch