Issue 42: consistency of NSEC3 parameter

[pfedick]

Hi,

I have implemented a part of #42 as a new policy "nsec3-consistency": All parameters of the NSEC3 records (algorithm, flags, iterations and salt) must be the same in the whole zone.

I have not implemented a check against the NSEC3PARAMS, because I found out, that already a lot of errors occur, when they differ from NSEC3.

Regards, Patrick