Previously, we were applying defaults before the user had completed
registration. This meant that the number of invisible users was
incremented when the user connected, and then the total was incremented
when registration was completed.

Now both counters are updated at the same time. If a user disconnects
prior to registration, +i has not yet been applied so it would not be
decremented.

Or try to, anyway

The isupport is always a pure function of the Config object,
not of Server or any globals.

1. If both fingerprint and hash are specified, require both instead of either
2. Implement auto-oper on connect

Includes a partially backwards-incompatible config change

Workaround for #661: this makes the `CAP LS 302` line from the default config
fit on a single line, as long as the server name is at most 35 characters.