Merge with https://github.com/zfedoran/convert-to-threejs-json/ Apr 28, 2013 version
coverter_to_threejs.py: copy textures of import files to output folder, and fix dae model's get uv index bug.
coverter_to_threejs.py: fixed issue #3808, and handling some issues about the asset's texture copy.
Merge branch 'converterEnhance' of https://github.com/DaoshengMu/three.js into dev