List-like arrow for MIDI import operations
more fixes for spanners & import
Merge pull request #454 from trig-ger/midi_arrow

List-like arrow for MIDI import operations
fix measure search when instrument is hidden
fix #22451: MuseScore should make it impossible to load styles made in previous version
create beams in MusicXML import even if stem direction is not explicit
When, for a change in the cross-measure value setting, notes change from stemmed to stemless (or vice versa), stems are not properly removed or added.
Breves are vertically misaligned and in different horiz. positions when 'up-stemmed' and 'down-stemmed' (assuming the had a stem).

Fixed by adding the Note::HEAD_BREVIS case when centring note heads.
Merge pull request #456 from mgavioli/cross-measure_values_stems

Cross-measure values: fix stemmed-stemless shape changes
Merge pull request #457 from mgavioli/Brevis_vert_align

Brevis note heads vertical alignment
simple implementation of repeat (R) last chord in input mode
more fixes for line editing
fix #22023 MusicXML import/export of simple grace notes
fix accidentals for trills
fix possible crash with image
do not tie grace note
more fixes for null images
fix position of number for multimeasure rests
fix #11661: grace notes are not part of selection
fix crash when undo paste of acciacatura