adjusted to latest VexFlow version
Merge branch 'vexflow-updates' into all
removed clef def from m2v-ovrr, adjusted clef handling to latest VF
features
switched to VF's labeling of breves; removed redundant code
Merge branch 'vexflow-updates' into all

Conflicts:
	src/Converter.js
	src/StaffInfo.js
Merge branch 'all'