GSoC 2020: New and Improved Multimeasure Rests and Measure Repeats in MuseScore

Demonstration of results of Google Summer of Code project for MuseScore. I added support for adjusting the style of multimeasure rests, switching to old-style multimeasure rests, preventing line breaks between selected measures, automatically numbering one-measure repeats, and creating two- and four-measure repeats with MIDI playback support and the ability to import from and export to MusicXML format. Get the code at https://musescore.org/en/node/309770