handle style change for Marker
Fix for issue #24339
Slurs between voices will now save and restore properly.
The MuseScore debugger has not been fixed to display the cross-voice
property of such slurs.
fix #24350: markings lost after timesig change

Annotations were completely lost, spanners placed incorrectly.  Also,
repeat measure symbol caused hang.  These are fixed.  Key signatures
still can get messed up, at least until reload.  And barline styles are
lost even when they coincide.
add test
Corrected both reading and writing.
A slur is not equivalent to most of the other spanner elements since it
is related to specific voices, not once but twice.
Remove references to "this"
fix repeat barlines & "free" annotations

* preserve repeat and other barlines where possible
* preserve "free" annotations - like chord symbols in the middle of an
otherwise empty measure
* update test
add score symbols to SimpleText
replace FreeSerifMscore by plain FreeSerif font
Updated compatability test for slurs.
enable kerning for consecutive score symbols (like fff)
change symbol palette in text input to use score symbols
implement fallback font (Bravura) for symbols in text
Merge branch 'master' of github.com:musescore/MuseScore
Read prior version mscx files correctly by defaulting to single voice
slurs
fix 24377: crash on create parts if tbox present
fix #24380: convert 1.3 text frame settings to spatium
Merge pull request #656 from Jojo-Schmitz/warnings

Fix warnings under Windows and with Qt-Creator
Merge pull request #657 from Jojo-Schmitz/orig_txt

getting rid of some useless window titles
Merge pull request #658 from MarcSabatella/24350-markings-after-timesig-change

fix #24350: markings lost after timesig change