docs: function createOutputDirsAsync(buildOptions) {
    var outputDirs = new OutputDirs(buildOptions);
  
    var tasks = [];
    tasks.push(makeDirAndParents(outputDirs.tmp));
    tasks.push(makeDirAndParents(outputDirs.gen));
    tasks.push(makeDirAndParents(outputDirs.build));
  
    return kew.all(tasks)
        .then(function() { return outputDirs; });
  }