Makes Kyber-AVX run on MacOS (#251)

* 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

In light of #251

* Integrate Kyber-AVX2 into PQClean

* Fix types and formatting in Kyber

* Workaround a valgrind crash

* Remove comment in shuffle.s

* Remove some extraneous truncations

* fixup! Fix types and formatting in Kyber

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

* Replaced round-1 Kyber code with round-2 Kyber code (not yet cleaned/namespaced)

* Namespacing for Kyber

* Some more work on round-2 Kyber (more namespacing)

* Added missing files

* Round-2 Kyber768 now passing all tests under Linux

* Various small tweaks to make MS compiler happy

* Two more tweaks for MS compiler

* Added Kyber512 and Kyber1024 (round-2 versions)

* Making MS compiler happy

* More fixes for MS compiler

* Replaced round-1 Kyber code with round-2 Kyber code (not yet cleaned/namespaced)

* Namespacing for Kyber

* Some more work on round-2 Kyber (more namespacing)

* Added missing files

* Round-2 Kyber768 now passing all tests under Linux

* Various small tweaks to make MS compiler happy

* Two more tweaks for MS compiler

* Added Kyber512 and Kyber1024 (round-2 versions)

* Making MS compiler happy

* More fixes for MS compiler

* Started more cleanup work on Kyber768

* Replaced round-1 Kyber code with round-2 Kyber code (not yet cleaned/namespaced)

* Namespacing for Kyber

* Some more work on round-2 Kyber (more namespacing)

* Added missing files

* Round-2 Kyber768 now passing all tests under Linux

* Various small tweaks to make MS compiler happy

* Two more tweaks for MS compiler

* Added Kyber512 and Kyber1024 (round-2 versions)

* Replaced round-1 Kyber code with round-2 Kyber code (not yet cleaned/namespaced)

* Namespacing for Kyber

* Some more work on round-2 Kyber (more namespacing)

* Added missing files

* Round-2 Kyber768 now passing all tests under Linux

* Various small tweaks to make MS compiler happy

* Two more tweaks for MS compiler

* Added Kyber512 and Kyber1024 (round-2 versions)

* Making MS compiler happy

* Making MS compiler happy

* More fixes for MS compiler

* More fixes for MS compiler

* Started more cleanup work on Kyber768

* Kyber768 passing all tests locally

* Kyber512 passes all tests locally

* Kyber1024 now also passing all tests locally

* Now passing all tests with -Wmissing-prototypes

* Local tests (on Linux) passing again