Fix to IP addrees handling in Vista based os'

[Mr. Kimmo P.]

Vista based operating systems returns IPV6 addresses as the first address in the IPAddress list collection. I made new function to library (FTPConnection class)

        private IPAddress GetLocalAddressIPV4()
        {           
            IPAddress[] result = Dns.GetHostAddresses(System.Environment.MachineName);
            for (int i = 0; i < result.Length; i++) {
                if (result[i].AddressFamily == AddressFamily.InterNetwork) return result[i];
            }
            return null; //this is error and means that no IPV4 address found
        }

[Mr. Kimmo P.]

Sorry about the typo in subject.