fix typo and warning on startup
fix #30586, create segments on demand when cloning staves
fix #30671, make link staff undoable when creating parts
fix import of gtp, clefs (GPX) and key sigs (all) were generated on each measure
fix guitarpro mtests
Merge pull request #1216 from MarcSabatella/gptest-update

fix guitarpro mtests
fix some pre-translation issues