Also fixed a typo in RaceTrack.asset.

Modified the pit prefab (sorry Claire), the surrounding blocks clashed with neighbouring pits/walls/water/etc.
Starting the game will now take you to the 4-player alpha racetrack rather than Colour Collide.
Camera now scrolls along the racetrack level at a rate of 1 block per turn. Currently nothing happens to people who fall behind it, except that you can't see them.
Pets will no longer paint blocks in their colour. (I had to modify the ColorCollide.cs script for this, as I could not figure out how to turn a script into a .asset object as was done for ColorCollide.asset.)