bug fixing decrmementCritters on death and on end tile

nagging issue where if a critter in the middle of a wave died, it did not decrement. critters at end tile also did not decrement. fixed now. critter death handling was done partly in handleCritterRemoval() and in the attack loop. i just consolidated it all to handleCritterRemoval() and it works fine now.
@sli-fox  @markmssd  @AjayAujla  @mdubey2014