DN out of order with dict, use list(); no inet_pton for windows; unicode general names

* fixed _build_dn to list from dict to preserve DN order.
* _ip_str_to_octets changed to netaddr IPAddress from socket as no pton
support for windows. should now be cross platform for x509v3
subjectAlternativeNames IPv4 and IPv6
* fixed encoding in _build_general_name where input is unicode