New hash API: Update

[Piotr Szturmaj]

Johannes Pfau wrote:
> I'm mostly finished with my hash API proposal. I also ported the
> existing crc, md5 and the proposed sha1 hash to this new API.
>
> I changed the namespace to std.util.digest. Andrei once said he thinks
> std.digest/std.hash is a too narrow package and someone else said
> putting crc into std.crypto.digest is ridiculous. So I did what tango
> and other libraries do and created a std.util module.
>
> I think std.uuid would also fit well into std.util so it'd become
> std.util.uuid.

I vote for std.crypto.hash and std.uuid. CRC, Adler and others could fit 
in std.checksum.