Two views: the editor's and the reader's

A switch in the header: "Editor's view" (the site as published) and "My view" (minus what I have read, plus my notes). The editor of record is the first named audience; the switch is built so more audiences can be added (each a named filter over the same pages).

Done when: the switch persists, every list obeys it, and the front page says which view it is showing.