add on-goodbye-event

This change requires a coordinated change to the snip-lib pkg and to
the gui-lib package. The docs are in the gui-doc pkg and yet point to
the snip-pkg as the containing pkg, so I updated the version number
for snip-lib and left the version number for gui-lib alone
added insert/io
I'm also responsible for the gui pkgs
add support for the ellipses in the error messages

according to the promise in the "Error Message Conventions"
section in the Reference