README: the tools table shows last_known_at_area and the confirmed /
last_known split, one paragraph on freshness and last-known answers,
and the "never returned as a location" line now says what a stale
position does come back as. CHANGELOG.md started, with 0.1.1
(unreleased) and 0.1.0. package.json and package-lock.json at 0.1.1.
Not published.