Copies a directory.
# S3 method for default
copyDirectory(from, to=".", ..., private=TRUE, recursive=TRUE)The pathname of the source directory to be copied.
The pathname of the destination directory.
Additional arguments passed to
    file.copy(), e.g. overwrite.
If TRUE, files (and directories) starting with
        a period is also copied, otherwise not.
If TRUE, subdirectories are copied too,
        otherwise not.
Note that this method does not use copyFile() to
  copy the files, but file.copy().