Update the city collision

Yeti: The city collision is updated. I am going to add a car in the
environment to do further test
Update README.md
Update README.md
Update the raw car model and the car collision

Yeti: I put a simple car model(The window is not clear enough) inside
the city and add the car collision to the scene.
Correct the Scene Size

Yeti: I correct the scene size for the city according to the mocab space
size
Script of car movement

Yeti: Updated the car movement. (Both wii controller and keyboard)
New version for the car movement and model

Yeti: I updated the raw speed label and a new car for the scene and
adjust the position for the car
Merge pull request #1 from houllion/Yeti's-branch

Yeti's branch