* sha3: remove old implementations
* sha3: new implementations
* picnic: use liboqs sha3 and sha3x4
* frodo: use new sha3x4 interface
* sphincs: use liboqs sha3x4
* fixup
* skip test_spdx on xkcp_low directory
* xkcp_sha3: explicit casts to avoid narrowing warnings
* xkcp_sha3x4: explicit casts to avoid narrowing warnings
* sha3: disable platform specific xkcp if OQS_PORTABLE_BUILD
* sha3: fix Wcast-qual warnings on clang-9
* fix 'reset' functions
* xkcp_sha3: skip fastloop call if input is not long enough
* xkcp_low: Enable lane complementing for plain-64bits
* xkcp_low: remove Kravatte definitions from times4/avx2
* Add common OQS_MEM_aligned_alloc and OQS_MEM_aligned_free
* Require both OQS_USE_OPENSSL and OQS_USE_SHA3_OPENSSL to enable OpenSSL's SHA3
* Fix some undefined behaviour in KeccakP-1600/plain-64bits
* Fix some undefined behaviour in KeccakP-1600times4/avx2
* Expand shake tests
* Add sha3x4.h include to oqs.h
* Add xkcp_low license info to readme [skip-ci]
* Add copy_from_xkcp scripts [skip-ci]
* SPDX License Info for new scripts [skip-ci]
