Legal stuff

[Tim Angus]

I just checked in a GPL MD4 implementation derived from the Linux
kernel. I'm not 100% sure it's 64bit and big-endian safe, so some
testing on x86_64 and ppc would be good.

The advertising clause in the Berkeley license is not GPL compatible.
Fortunately there is a precedent for simple removing it:

ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change

So I suggest we do just that.. unless anybody disagrees?