* Put AES ctx on the heap

This forces people to use the ``ctx_release`` functions, because otherwise there will be leaks

* Put fips202 on the heap

* Add much more docs for fips202.h

* fixup! Put fips202 on the heap

* Put SHA2 on the heap-supporting API

* Fix clang-tidy warnings

* Fix unreachable free() in falcon

* Fix McEliece8192128f-sse GNU Makefile

There are schemes, like SABER (#192) that have more than one principal
submitter. Consistency warrants that we turn it into a list for all
schemes and don't do something with allowing either a str or a list:
that would just be very annoying to parse.

Closes #194