don't implode voices of different rhythms

as this it can lead to data loss.
On imploding staves it could lead to some incorrectness, but as the old
staves are still there, this can get spotted and fixed.
make systemBarLineType a property
fix 40241: Recent scores menu doesn't show imported files
hide navigator by default
fix crash when opening scores with 0 measure (old templates)
Fix 40901: Midi remote control Augmentation dot doesn't work
fix #37986: lupdate doesn't like forward declaration enums... see http://www.qtcentre.org/threads/59673-lupdate-fails-to-detect-context-for-class-in-namespace
Merge pull request #1516 from rtega/404-new-feature

Fix 40901: Midi remote control Augmentation dot doesn't work
Merge pull request #1507 from Jojo-Schmitz/implode

don't implode chords of unequal duration
fix #29931: Custom key signatures do not show
fix mtest compilation
fix #41031: add flugelhorn to jazz genre
Merge pull request #1520 from MarcSabatella/41031-flugelhorn-jazz

fix #41031: add flugelhorn to jazz genre
Add test for Grand Staff instruments
Fix instrument names for the same channel
Add test for instrument names of the same channel
Add MIDI import test for grand staff detection
Fix #41011: Wrong instruments in MIDI file
Add MIDI import test for 3 staff organ
Show manual and pedal captions for organ; show instr + track name