musicxml header version is now 3.1
musicxml header version is now 3.1

grame-cncm/libmusicxml,dfober/libmusicxml,grame-cncm/libmusicxml,grame-cncm/libmusicxml,dfober/libmusicxml,grame-cncm/libmusicxml,dfober/libmusicxml,grame-cncm/libmusicxml,dfober/libmusicxml,grame-cncm/libmusicxml