Update Windows installer to support IPv6

After significant email conversation, the plan is:

• add a dialog to the installer
• based on the user response, modify the service-register script that is invoked (NOT static_config)
• result is that the Windows service will start with the appropriate args based on user response
• however, in order to change this value, user would need to re-run the installer, or at least we'd need to provide a script for them to run to re-create the service

and the specific changes to the service-register script are:

[1] The –name parameter must take the value babysitter_of_ns_1@::1 for IPv6 (currently babysitter_of_ns_1@127.0.0.1 is used for IPv4)
[2] Add –proto_dist inet6_tcp to the –args parameter (this will be –proto_dist inet_tcp for IPv4)
[3] Add –ns_server ipv6 true to the –args parameter (this will be –ns_server ipv6 false for IPv4)