appveyor.yml: automatic builds of Windows executables
appveyor.yml: automatic builds of Windows executables

Majlen/zstd,Majlen/zstd,inikep/zstd,Cyan4973/zstd,Cyan4973/zstd,ds77/zstd,Majlen/zstd,inikep/zstd,ds77/zstd,inikep/zstd,inikep/zstd,ds77/zstd,Majlen/zstd,Cyan4973/zstd,ds77/zstd,Cyan4973/zstd,Cyan4973/zstd