Copies a directory.
# S3 method for default
copyDirectory(from, to=".", ..., private=TRUE, recursive=TRUE)Returns (invisibly) a character
vector of pathnames copied.
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.
Henrik Bengtsson
Note that this method does not use copyFile() to
  copy the files, but file.copy().