Made pod racer controllable

Added xbox controls to pod racer engines. Added ropes between engines
and pods. Refactored code to be in the PodRacer class. Added a
GameManager.
Various Improvements

Added line between pods.
Removed camera movement for now.
Added comments.
Moved variables to tuning.lua.
Merge pull request #1 from michaelwiktorek/simon

Made pod racer controllable