fix #23680: import all courtesy accidentals
fix #23680: xml-import all courtesy accidentals
fix #23680: xml-import all courtesy accidentals
fix 23680: some corrections
fix pianoroll crash if there is no score
fix crash in texttools.cpp
fix pianoroll editor; editing event ontime and length
Merge pull request #734 from Isensee/23680-import-courtesy-accidentals

23680 import courtesy accidentals
add test for import of courtesy accidentals seefix #23680