Update requirements and implement new pre-publication check

From the user's list:

Why is the SOA ttl considered for the check? DNSKEY TTL I'd understand,
but SOA?

Yes, that sounds strange. The first ZSK should be pre-published according to this time:
Ipub = Dprp + min(TTLsoa, SOAmin)

The following ZSK:s should be pre-published using this time:
Ipub = Dprp + TTLkey

We will have a look at this.

From the spec ( http://trac.opendnssec.org/wiki/Signer/AuditorRequirements ) :

"Give an error if a key is seen in use without it having first been seen as prepublished for a time of at least the zone SOA TTL. [E]"

Should the specification be changed?