Some Optimizations [141101-0010]

1. The speed of loading models and textures are hugely increased.

2. The problem that our program freezes when it's resumed is solved.

3. Cleaned up some codes.

Next step for me: study Shading.
Next step for all of us: Learn to use VoIP. Begin to write
GameObjectUpdaters.

By Zhongzhi Yu (Mark)