0. Maximum parity with upstream code
1. Added Apache-required modification notices
2. Added Apache license

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

In particular, allow hostnames without periods (like on a LAN).
This shouldn't be a client compability concern since we allow
vhosts without periods.

Includes a partially backwards-incompatible config change

tor-listeners.listeners was checked against listen,
but listen is obsolete now, so config load would fail
on a config that used the new style `listeners` instead of
`listen` --- unless tor-listeners.listeners was empty, which
it should be under the new style, but there's no need to enforce
that

Fixes #505

eliminates Server.configurableStateMutex

* limit the total number of registrations per account
* when an account is unregistered, unregister all its channels