add a `sni' option for the `proxy' block: the given name is used instead of the one extracted by the `relay-to' rule.

Currently dogfooding this patch at gemini.sgregoratto.me. To test, run the following command and look for the "OCSP response" header: openssl s_client -connect "gemini.sgregoratto.me:1965" -status

This adds a barebone dumping of the parsed configuration. It is not complete, but I'm interested in dumping the full path to `cert' and `key' in order to write some scripts that can inspect the configuration, extract the certificates and renew them when expired automatically. It's not easy to parse gmid configuration otherwise because the syntax is flexible and users can use macros. Instead, the idea is to run gmid and let it dump the configuration once it's been parsed in a static and predictable format. Now is possible to parse gmid configuration with, say, awk or perl.

bump version number