hetznerctl: Allow to show details about a server.

This shows more info about one or more specific servers than the list
command (which only shows the main ip, name and product).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
server: Allow to get IP addresses of a server.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
server: Allow to get IPv6 subnets of a server.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
hetznerctl: Show information about Subnets/IPs.

This shows information about IPv4/IPv6 subnets and IPs when issuing a
"hetznerctl show <ip>".

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Don't be specific about IPv4/IPv6.

This is somewhat blurry as the /ip/ and /subnet/ requests can contain
either IPv4 OR IPv6 addresses (not sure on /ip/ though) with no flag
that specifically distinguishes them.

So, in the future we might want to add our own detection routine to
decide whether an IP address is IPv4 or IPv6 (which should be fairly
easy).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Bump version to 0.5.0.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>