fix #39851 - Crash on load of MusicXML file with pedal change but no start
fix several 'node not implemented' warnings
fix MusicXML export of overlapping ottavas (part of #30791)
fix MusicXML export of overlapping hairpins and trills (part of #30791)
update existing testfiles
fix #30791
remove spurious debug message
Merge pull request #1512 from lvinken/musicxml-fixes

Musicxml fixes