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).

we still have an hardcoded list, but this implements the API needed to modify the mappings.

err/warn is not available on some systems (unfortunately!) and in any case don't play well with our daemon mode (that closes std{in,out,err}). Use our fatal that is daemon-aware.

cgi.c wasn't really needed; it better to group all the server related functions together, cgi or not. Now gmid.c contains only startup and utility code.

with the split into two process, the call to daemon was lost

this way, we can sandbox the listener with seccomp (todo) or capsicum (already done) and still have CGI scripts. When we want to exec, we tell the executor what to do, the executor executes the scripts and send the fd backt to the listener.