Related to #79

Add FrodoKEM-640-SHAKE reference implementation

Helpful for local builds, even though it has no effect on fresh CI builds

Namespace the #define constants.

Does this slightly uglily, but it should work.

Add incremental SHA2

Add incremental API for SHAKE and SHA3

It's nice to be able to test this, but it does not need to happen
for every CI run.

Windows tests

use randombytes in functest

Got dropped by the rebase

Work around missing clang-tidy on Travis

Also check if valgrind is available

Hopefully quicker on Windows

Git takes care of this, and it breaks the checkouts on Windows

Also try to install it on AppVeyor

LIB is already an environment variable on Windows

Make all apis use the uint8_t and size_t types

Move clang-tidy into python-based tests

Clean up tests

Modify the tests to no longer construct the classes multiple times and
to have them make use of the new helpers.make() function.