* The IPv6 address parser now handles IPv4 mapped IPv6 addresses which
take on the form ::ffff:x.x.x.x.
* Implement Display for IPv4 mapped IPv6 addresses
* Implement From<IPv4Address> for IPv6Address
Fixes#86
- Add the ipv6 feature
- Ensure a travis build with the ipv6 feature enabled.
- Add the necessary infrastructure to wire for ipv6 support.
- Ipv6Address
- Ipv6Cidr
- Add Ipv6 Address and Cidr parsing to parsers
- Add basic tests.
This is more likely to result in downstream confusion than not.
Let downstream code decide exactly what it wants to do with
an empty string; be conservative here.