Contribution to your updater script

[gabbel]

I remarked that the script which has been updated 8 years ago does no longer work.
Therefore I did some changes.
These are:

• Support for ipv6 AAAA records.
• Support for ipv4 A records remains the same.
• Support for multiple host entries separated by space remains.
• Detect interface of the default route in case that non has been provided.
• The temp file (per host) now holds both records (ipv4 on fist line, ipv6 on second line.
• I have tested the changes on openwrt.

[Neustradamus]

@gabbel: Any progress on it?