Issue #238: Fixed skunk AVX2.
Issue #239: Faster AVX2 & AVX512 for skein +44%, skein2 +30%, plus marginal
increases for skunk, x16r, x16rv2, x16rt, x16rt-veil, x16s, x21s.
Faster anime VAES +57%, AVX512 +21%, AVX2 +3%.
Redesigned code reponsible for issue #236.
