fix #25613
fix #25616: Rehearsal mark from MuseScore 1.3 causes bad layout and crash
update Gonville
fix #23006
update mtest for guitarpro
fix #25618
enabling more metaTags
fixing typos found along the way
fixing the regression test files in mtest
improving content for platform tag
removing "Platform" tag from all mscx files

as it is case sensitive and really should be "platform" and as such
would be ignored during tests
rebase and adjusting new regression test files