merge multi threading to master branch

- updated zstd to latest devel release
- lz4, lz5 and zstd is included now
- all three support threading

CPP/7zip/UI/Explorer/ContextMenu.cpp

@@ -283,8 +283,12 @@ static const char * const kArcExts[] =
     "7z"
   , "bz2"
   , "gz"
+  , "lz"
+  , "lz4"
+  , "lz5"
   , "rar"
   , "zip"
+  , "zst"
 };
 
 static bool IsItArcExt(const UString &ext)