Expose low-level scryptsalsa208sha256()
Merge branch 'master' of github.com:jedisct1/libsodium

* 'master' of github.com:jedisct1/libsodium:
  Link memset_s presence test
Use uint64_t for 64-bit types instead of unsigned long long
Do not violate strict aliasing in int128_aes128ctr.c