code: function deleteIfEmpty(file, options) {
    options = _.opts(options, {deleteDirs: true});
    return fileDelete(file, _.extend(_.opts(options), {onlyEmptyDirs: true}));
  }
docs: Delete file or empty directory
  @function $file~deleteIfEmpty
  @param {string} file
  @param {Object} [options]
  @param {string} [options.deleteDirs=true] - Also delete directories
  @returns {boolean} Returns true if the path was deleted or false if not
  @example
  // Delete $app.installdir if it is empty
  $file.deleteIfEmpty($app.installdir);
  // => true