code: function flags(o, pre='', z='') {
    for(var k in o) {
      if(o[k]==null || k==='stdio') continue;
      if(Array.isArray(o[k])) z += ` --${pre}${k} "${o[k].join()}"`;
      else if(typeof o[k]==='object') z = flags(o[k], `${pre}${k}_`, z);
      else if(typeof o[k]==='boolean') z += o[k]? ` --${pre}${k}`:'';
      else z += ` --${pre}${k} ${JSON.stringify(o[k])}`;
    }
    return z;
  }
docs: Generate flags for console.