Use streaming construction to hash files

[cmuratori]

To allow for hashing files larger than available memory, and to prevent possible incompatibilities with ftell on 32-bit builds, I'd like to stop reading files into memory wholesale and start using a fixed-size buffer that gets repeatedly fread() and handed to Meow as a chunk.

- Casey

[NoHatCoder]

I'd say that the point of an example program is to show how all the features of a library is used, we should demo both chunked and single call, and also custom seeds. It would also be good if the example program would self-check by comparing the generated hashes to known values.

Am I by the way the only person who don't really get example programs that take command line arguments? I just want some code that I can copy-paste for a starting point, and mess around with to see how it is working, command line stuff just slows down my modify-test cycle.

[cmuratori]

Removing the command line arguments is easy enough I suppose - we would just feed it random data instead of files at that point, I guess. - Casey