[Opendnssec-develop] Defining KSK rollover schemes

[sion at nominet.org.uk]

> > isn't DoubleRRSet == DoubleDNSKey + DoubleDS ?
> >
> >    jakob
>
> Effectively, yes.
>
> You are rolling both the DS and the DNSKEY at the same time, so
> intervals depend on the parameters of both the parent and child zones.

I was going to leave this option until last, and will happily postpone it
to after v1.1 if there are other things to do or if I run out of time.