transposeKey() no longer returns keysigs with more than 7 sharps/flats
transposeKey() no longer returns keysigs with more than 7 sharps/flats
Issue #12918: double bar disappearing when removing courtesy key sig
Issue #12918: double bar disappearing when removing courtesy key sig
Mandola is usually written in Treble clef 8vb
so musescore should also use that as a default.

Tuning of a mandola is g-d-a-e one exactly the same as a
mandolin just one octave lower - not equivalent to a viola obviously
so the ranges also had to be fixed.
tune notes affected by micro-interval accidentals

Uses the default settings of the microtune plugin (which, having a GUI,
can't easily get ported to the new QML plugin style) plus Koron and Sori
Partial fix for Issue #19506

Prall and mordent now play correctly
low level optimizations
more small low level optimizations
replace some qt container with hand crafted single linked list
fix regression tests