[atlas] v6 support

mornin'antony,

> When the UI got updated, that is close to magic:) I can't explain!!

i demand a full refund!

> One day we shoule improve the UI; no idea when. To do it right we have
> to show multiple addresses and gateways. The probe can have multiple
> V6 addresses. When it receives multiple RA(different prefixes) and
> static IPv6 address it ends up with multiple V6 gateways too. Then it
> is a bit messy to show.

i will refrain from heresies about RA and link local

> Just now you switched to static V6. Yes,there was some down time, but
> it is back now:)

i was a bit amazed at the length of down time

> Now the fun begins, because the probe has two v6 address and two
> gateways, ::1 and the one it got via RA!

maybe, when it is statically configured it should drop what it learned
via RA?  hard call, as RA is a poor geek's vrrp6.  sigh.

randy