their return value is no longer used, it's only confusing at this point.

instead of having a flag to discern between two different behaviours in S_SENDING, split that state into S_SENDING_FILE and S_SENDING_CGI (this will also make it easier in the future to add other sending states). While there, also get rid of `goodbye' and make start_reply advance the state machine by itself.

make sure redirect starts with /. This also requires a tweak in check_path, in the case we go open_file -> send_dir -> open_file -> check-path and the path starts with a slash.

this also gives a chance for users to use the default host even if SNI is missing.

the new logging code was crashing if the client didn't support SNI or if required an unknown vhost: this because we short-circuit in handle_handshake to an error, so c->iri isn't populated yet (we don't even read the request). fixes #1

now we log the full IRI requested (before was only the path) and the response line (even for CGI).

was probably added to distinguish between AF_INET and AF_INET6, to use different functions for logging. But it wasn't really used, and now we use getnameinfo anyway.