Populating neighborhoods
ModelSwarm: Pick out neighbors, check if boundary conditions hold and call player to add to his list:
-setNeighborhood: (id) player atDX: (int) dx DY: (int) dy {
if ([self validX: x+dx Y: y+dy]) {
[[player getNeighborhood] addLast: [world getObjectAtX:x+dx Y:y+dy]];
-(BOOL) validX: (int) x Y: (int) y {
return (((x >= 0) && (x < worldSize)) && ((y >= 0) && (y < worldSize)));