IPv[46] parsing

[Dridi Boukelmoune]

> The other thing that I mentioned on Monday is modifying std.ip() to accept
> [::1] and [::1]:80 as well.

It is kind of weird to have an IP address (as in std.ip) accept a
port. It would probably be better to have something like std.addr for
that. The underlying VCL_IP is confusing with this regard.

My two cents:
- std.ip could revert back to expecting "::1" instead of "[::1]"
- std.addr could be used for the ip:port notation (as in varnishd -a)
- documentation should clarify the ambiguity

Cheers,
Dridi