Copy source file src to destination file dst.

CopyDir recursively copies the source directory src to destination directory dst.

CopyDirExclude recursively copies the source directory src to destination directory dst, except for paths contained in excludePath.

Download file from url and write it to filepath.

Exists checks if filename exists already.

IsBinary returns true if filename is binary and false otherwise.

List all entries in dir return them as string array.

RemoveAll removes all files and directories in path except the ones given in excludePaths.