Change out IO::Socket{,::INET} for IO::Socket::IP.

This passes with the patch for IO::Socket::SSL here: https://rt.cpan.org/Public/Bug/Display.html?id=75218 . So as soon as that's released, we should be able to bring this in and have everything work. I've added a few tests to be sure everything still works and they all pass. If you've not got access to a machine with 'v6 I can give you a shell in a couple of different places with native (no tunnel/6t4/etc.) dual stack.