- updated zstd to latest devel release - lz4, lz5 and zstd is included now - all three support threading
- made an extra zstd.mak file - removed Format7zZStd - SFXSetup also has zstd now - the big 7z.dll is backward compatible to: 0.5 .. 0.7 - the small 7za.dll has only support for zstd 0.8