code: function createTempDir(options) {
    options = _.opts(options, {cleanup: true});
    return _createTemporaryPath(fs.mkdirSync, options.cleanup);
  }
docs: Create temporary directory
  @function $os~createTempDir
  @param {Object} [options]
  @param {boolean} [options.cleanup=true] - Mark the directory to be cleaned up on exit
  @returns {string} - Temporary directory created
  @example
  // Create a temporary directory that will be deleted at exit
  $os.createTempDir();
  // => '/tmp/1453474785995.4712'
  @example
  // Create a temporary directory but do not automatically clean it up at exit
  $os.createTempDir({cleanup: false});
  // => '/tmp/1453824141131.3015'