message: Add hi-res skybox.
diff: <option value="solid">Solid</option>
  <option value="sor_sea/sea_;JPG">Sea</option>
  <option value="mp_plains/plains-of-abraham_;png">Plains</option>
  + <option value="Teide/Teide_;jpg">Desert</option>
  </select>
  <br>
  <input id="skybox" type="checkbox"> Skybox
  