Van Logic v1

Modify onScannedRobot to call: onScannedAnimal, onScannedStone,
onScannedTreasure, onScannedVan.

Removed logic related to Asteroids & Spaceships: onScannedAsteroid,
onScannedSpaceship, isDummyAsteroid, isCircularAsteroid,
isLargeAsteroid.

Removed logic related to gun & fire.

Removed unused comments.

Reordered methods.