cf method get_host, replace with query

[icing]

Connection filters had a method get_host() which had not really been documented. Since then, the cf had the query() method added. Replace the separate get_host with query.

Add CF_QUERY_HOST_PORT as query to connection filters to retrieve which remote hostname and port the filter (or its sub-filter) is talking to. The query is implemented by HTTP and SOCKS filters, all others pass it through.

Add Curl_conn_get_current_host() to retrieve the remote host and port for a connection. During connect, this will return the host the connection is talking to right now. Before/After connect, this will return conn->host.name.

This is used by SASL authentication.