We are trying to make the `hashes` crate easier to read and also
possibly parseable by machines to see what is different where.
Move the test and bench code into separate files. Make special effort to
keep formatting as is so the diff is easier to review. We will run the
formatter in the next patch.
Internal change only.
There are five modules in `hashes` that implement cryptography (i.e.
have a `process_block` function). For each of them create a new
submodule called `crypto` and move the code there.
Code organisational refactor only, no logic changes.
In preparation for removing a bunch of macros move all the modules to
`<mod>/mod.rs`.
Do so by running the following shell:
```bash
for mod in hash160 ripemd160 sha1 sha256 sha256d sha256t \
sha384 sha512 sha512_256 siphash24 hkdf hmac; do
mkdir $mod
mv "$mod.rs" "$mod/mod.rs"
done
```
Internal change only.
Tobin C. Harding