Added "astrobwt-avx2" parameter in config.json, it's turned off ("false") by default.
4-5% speedup on CPUs with proper AVX2 support (AMD Ryzen starting with Zen2, Intel Core starting with Haswell).
There will be no speedup on the following CPUs:
- Intel Pentium/Celeron don't support AVX2
- AMD Zen/Zen+ have only half-speed AVX
GCC compiled version is faster without AVX2, MSVC compiled version is faster with AVX2