use QXmlStreamReader for xml parsing
enable musicxml support, move needed xml functions to musicxml code
fix all regressions detected by mtest
complete switch to QXmlStreamReader
fix reading of session xml file
fix regression: read instrument xml
fix another xml regression (lines)
fix drag&drop from palette
fix Range() read/write
fix mtest build
fix #19734
Align reading FiguredBass XML from score with the new XML reader
Merge pull request #174 from mgavioli/Fix_FiguredBass_XML_read

Fix FiguredBass XML read