initial: improve performance adding and removing KeySig
ChangeElement updates keymap for keySig change
Merge pull request #280 from heuchi/keySig_improvements

Fix #20573 and improve performance of KeySig handling
fix layout of grace note hook
honor beam mode NO for grace notes
move ledgerline and stemslash into separate files
fix stemslash layout
cleanups
Switching-Concert-Pitch Benchmark
test if accidentals updated for add, change and remove of keySig
corrections for keysig test
Merge pull request #282 from heuchi/concert_pitch_benchmark

Two new tests: tst_concertpitchbenchmark and tst_keysig