On logging in, don't get a new access token if there's one in the database
for this user. Log out link wipes the user's session, but not their database
entry. Those can be cleaned up periodically (after I add a last-used stamp).
Misfeature: user's setting is deleted, too, because it was only in the session.
Currently, this uses anonymous sessions. You log in to your instance, and you
get associated with a session. Your client information and account information
are persisted (created only if needed, reattached if not). Passwords are never
stored, only access tokens.
Only supports single user, lots of display elements not supported yet.
But it actually has something to show.
Actually display a home timeline.
Still only single user, doesn't correctly handle boosts, CWs, and
probably a lot of other things.
