fix build for Qt 5.3.2
fix duplicated entry
fix #10576: Local handbook doesn't open
fix #33371: MuseScore crashes while importing MusicXML file that was exported by Score Perfect 6
fix #33411: Adding Instrument to score with multi-measure rests enabled crashes MuseScore
hide local handbook behind -e option

as long as it doesn't have any usefull content
Merge pull request #1321 from Jojo-Schmitz/local-handbook

fix #10576: Local handbook doesn't open