Basically, fakelag was counting the time imposed by its own sleeps as though
the user had themselves paused for that amount of time. Therefore, if a user
sent a large number of consecutive commands, every other command would pause
for the expected throttle interval, but the subsequent command would be
processed instantly (you'd get two back-to-back commands). This resulted in
throttled users being able to send at double the expected rate.

1. Implement persistent channel keys (#208)
2. Persist changes to registered channel modes
3. Backend changes for persisting operator status (partial #198)

The sync.atomic documentation says:

"On both ARM and x86-32, it is the caller's responsibility to arrange
for 64-bit alignment of 64-bit words accessed atomically."

See discussion on issue; this might not be a complete fix but it's
definitely better than the current behavior.

Sequence of events:

1. client.nickTimer.Stop()
2. client.server.accounts.Logout(client)
3. accounts sees that client is no longer logged in, does client.nickTimer.Touch()
4. 30 seconds later, RandomlyRename resurrects the zombie client

Empty channels were only cleaned up on PART, not QUIT.

"There is no error reply for bad channel names."
<https://tools.ietf.org/html/rfc2812#section-3.2.5>