* 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

clang-tidy9.0.0 added a new check: bugprone-branch-clone
(https://releases.llvm.org/9.0.0/tools/clang/tools/extra/docs/ReleaseNotes.html)
This doesn't like both branches of an if are the same.
This lead to a warning in rainbow, as where the maximum of two values (which
are always the same) is computed in a macro.
I don't always agree with this warning, but here I think it's worth to
remove the macro.

* Enable valgrind exit errorcode

It seems we were not doing anything with the valgrind results... D:

* Use --exit-on-first-error if available

* Revert "Merge pull request #182 from PQClean/rainbow"

This reverts commit 8a008417fe988b48c8acc4aefc9c299a4d3c1645, reversing
changes made to d4b612fe9a.