Add accompaniment exit requirements to chanson idiom definition.
Add accompaniment exit requirements to chanson idiom definition.

craigsapp/humlib,craigsapp/humlib,humdrum-tools/minHumdrum,craigsapp/minHumdrum,humdrum-tools/minHumdrum,craigsapp/minHumdrum,humdrum-tools/minHumdrum,craigsapp/minHumdrum,craigsapp/humlib