This adds hash.go and creates a identityHash that is used for algorithms
that do their own hashing (ED25519) for instance.
This unifies the hash variable naming between dnssec and sig(0) signing
and removes the special casing that existed for ED25519.
This unifies the variable naming between sig(0) and dnssec signing and
verifying.
I didn't want to used crypto.RegisterHash as not to fiddle with the
global namespaces of hashes, so the value of '0' from AlgorithmsToHash
is handled specially in dnssec and sig(0) code.
Note that ED448 isn't implemented at all.
Signed-off-by: Miek Gieben <miek@miek.nl>
Miek Gieben