Mob refactoring.

Updates Bump() code.
Intents now use constants.
Simple animals can now use languages without overriding say().
There is now a difference between being able to smash normal and reinforced walls.
Reworks simple_animal/attackby so that constructs don't need to override it simply to add damage resistance.

code/modules/projectiles/projectile/change.dm

@@ -71,7 +71,7 @@
 		for (var/obj/effect/proc_holder/spell/S in M.spell_list)
 			new_mob.spell_list += new S.type
 
-		new_mob.a_intent = "hurt"
+		new_mob.a_intent = I_HURT
 		if(M.mind)
 			M.mind.transfer_to(new_mob)
 		else