Add RockHound

A RockHound gets the actors to be processed in the same way as a Critter. It removes any rocks in that list from the grid. A RockHound moves like a Critter.
Add BlusterCritter

A BlusterCritter looks at all of the neighbors within two steps of its current location. (For a BlusterCritter not near an edge, this includes 24 locations). It counts the number of critters in those locations. If there are fewer than c critters, the BlusterCritter’s color gets brighter (color values increase). If there are c or more critters, the BlusterCritter’s color darkens (color values decrease). Here, c is a value that indicates the courage of the critter. It should be set in the constructor.