code: func copyAppManifest(cdir string, appName types.ACName, dest string) error {
  	appInfoDir := common.AppInfoPath(cdir, appName)
  	sourceFn := filepath.Join(appInfoDir, "manifest")
  	destFn := filepath.Join(dest, "manifest")
  	if err := fileutil.CopyRegularFile(sourceFn, destFn); err != nil {
  		return errwrap.Wrap(errors.New("error copying image manifest"), err)
  	}
  	return nil
  }
docs: // copyAppManifest copies to saved image manifest for the given appName and
  // writes it in the dest directory.