See #2

We moved to SHA256 for compatibility with older versions of Python 3, and this hash is thus unchecked. It will only get out of date, so it seems better to remove it.

Closes #11

It's already available. Should speed up the build a small bit

It's poorly supported and reports false positives (See also #10)

Otherwise Make is vague if it did anything

We need to use find loops to exclude *.dSYM folders created by -g on
OSX.

This is a poor mans fix for the problem with the build, but what can you do 🤷

This means we must downgrade to SHA256, as SHA3 is not in hashlib.

This breaks the build, as Kyber and Dilithium currently are not
properly namespaced. More pressingly, this is not a long-term
solution: because of the way Makefile dependencies work,
one failing test now prevents all others from running.

We probably want to change the testing setup not to rely so heavily
on the Makefile, and instead call a Python or shell script.
Related, we may want to reconsider the single scheme / all targets;
this is becoming quite a mess in the Makefile, already.

Also fixes some tidy issues

Not sure why my local clang-tidy doesn't complain