proxy: allow multiple proxy blocks, matching options and validations as a side effect the order of the content of a server block is relaxed: options, location or proxy blocks can be put in any order.

allow to disable TLS when proxying requests

add `protocols' option to `proxy' rule

add `verifyname' option for `proxy' rule

simplify the proxying code it doesn't make any sense to keep the proxying info per-location: proxying only one per-vhost. It can't work differently, it doesn't make sense anyway.

support optional client certificate for proxy rule

add ability to proxy requests Add to gmid the ability to forwad a request to another gemini server and thus acting like a reverse proxy. The current syntax for the config file is server "" { ... proxy relay-to host:port } Further options (like the use of custom certificates) are planned. cf. github issue #7