minor version increasal -- by default for snap, for release optional.

Change-Id: I0996196656ffe60b57d93803713400365c09cd44
handle when debian/changelog is modified but staged (in index).

Change-Id: If78ae8b60f16211b36d294ab2f26be329da08e41
release

Change-Id: I518c177b1fb08d5c674d5eba9e8a71a5c19f578a