This is a C version of Bob Jenkins' spooky hash. The only advantage over
Bob's original version is that it is in C, not C++ and comes with some
test and benchmark code.
This is a very competitive hash function, but is somewhat non-portable.
It should work on both big and little endian architectures, but will
generate different hashes on them. It's also optimized for 64-bit
architectures. It will work on 32-bit architectures as well, but is much
slower there.
