If I delete a Published Instance, it should no longer show up in Recent Changes

(Bug, Closed -> Fixed, Priority: Critical, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )
Summary: Currently, they show up as somewhat empty, with a dead link.
For now, _getChanges() should simply screen these out. Possibly down the line, we might add a story to optionally include these (displaying them as "Deleted"), but for now they're just in the way.
This is a high priority for the Spirit Island FAQ.