title: Blender three json export errors
body: <p>I installed the three.js plugin for blender to export models to json format, i test it with very simple model contains materials of colors without textures but i get errors if i choose materials in options as in attached image, when i do not choose materials option i can export it but get error in reading it with JSONLoader, the error is "can not read property length of undefined" in three.min.js:264</p>
  
  <p><a href="https://drive.google.com/file/d/0B2F_KXzRsuI2bFdDUVJzcWVZcms/view?usp=sharing" rel="nofollow">the blender errors</a>
  <a href="https://drive.google.com/file/d/0B2F_KXzRsuI2R0VlUTNtM3E5NWc/view?usp=sharing" rel="nofollow">the exported json file</a></p>