Add AVX2 support

[OpenSourceAnarchist]

I'm not sure if this is as simple as I'm thinking, but over at https://sourceforge.net/projects/mpv-player-windows/files/, that version has a separate "-v3" binary which is compiled at the gnu x86_64_v3 standard, which is mostly limited to Haswell and newer processors. There's AVX2-only code that doesn't get used if support at compile-time isn't enabled.

I really don't use visual studio or WAP or anything msix usually, but from my understanding, the "Release" binary doesn't enable AVX2 by default. Moreover, the Windows Store would have to install the correct version, AVX2 or non-AVX2.

I figured when this was updated to 0.37, you might just take a look at this. It might be as easy as enabling it under Project Property Pages | Configuration Properties | C/C++ | Code Generation | Enable Enhanced Instruction Set or simply including /arch:AVX2. Thanks for considering it!!

[SilverEzhik]

Hmm. I'm actually not sure if the Microsoft Store offers a way to ship both of the binaries. Would love to be wrong here.