See discussion on #68.

don't need to send account-notify * (logout notification)
because either we never sent the initial account-notify
(if we are being logged out as part of fixupNickEqualsAccount)
or else we are immediately going to kill the client
(if we are being logged out as part of unregister/erase)

This avoids conditions where two sessions can be attached to the same client
while not logged into an account.

These commands search the registered nicknames/channels for ones
matching the provided regex, or return the entire list.

Only operators with chanreg (for ChanServ) or accreg (for NickServ)
capabilities can use LIST.

unregistering an always-on client would produce
"attempting to persist logged-out client : x"
because the client was always-on, but also being ejected

Explicit quit and ping timeout behave the same way,
but reattach after abandoning/losing the previous session
(without the break being detected server-side) is more aggressive
about replaying missed messages, at the cost of potential duplication.

Or try to, anyway

For irctest compatibility.

Fixes #775