fix #28476: disable systemFlag for chord symbols
fix #28571
fix #25867
fix #26546
ignore empty text element when reading score
fix #25472
Fix MIDI import panel on file close or switch
Fix end() iterator increment
Fix moc warnings on headers that do not require QObject
increase number of cpus used for travis compilation
Merge pull request #1081 from trig-ger/midi_fixes

Fixes for MIDI import
fix some strings
fix #25806
fix warning Interval previously declared as a struct
fix #25896
fix #28661: Deleting palette doesn't work
implement 'never hide' flag for staff
fix #22579: remove visible & color from context menu
partial fix for #23324: links for section breaks & fret diagrams
link frames added after parts