Made host name and proxy name get stored in a 'struct hostname' and set

all things up to work with encoded host names internally, as well as keeping
'display names' to show in debug messages. IDN resolves work for me now using
ipv6, ipv4 and ares resolving. Even cookies on IDN sites seem to do right.

lib/transfer.c

@@ -805,7 +805,7 @@ CURLcode Curl_readwrite(struct connectdata *conn,
                               /* If there is a custom-set Host: name, use it
                                  here, or else use real peer host name. */
                               conn->allocptr.cookiehost?
-                              conn->allocptr.cookiehost:conn->hostname,
+                              conn->allocptr.cookiehost:conn->host.name,
                               conn->path);
               Curl_share_unlock(data, CURL_LOCK_DATA_COOKIE);
             }