Templates doesn't handle IPv6 IPs

```
(ruby) Addressable::Template.new('https://{host}').match('https://127.0.0.1')
#<Addressable::Template::MatchData:0x64adc RESULT:{"host"=>"127.0.0.1"}>
(ruby) Addressable::Template.new('https://{host}').match('https://::1')
nil
(ruby) Addressable::Template.new('https://{host}').match('https://[::1]')
nil
```