Added support for CURLOPT_RESOLVE

libcurl 7.21.3 introduces CURLOPT_RESOLVE. Here's a patch providing support for it. I really don't like the bunch of #ifdef's required to implement it without bumping up the minimal libcurl version required. But perhaps it's not such a bad idea since 7.21.3 is from Dec 2010...

http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTRESOLVE