Mob grab/eating refactor

This refactors the mob-eat-mob code and fixes a few bugs along the way.
- Bursting out of a stomach now has a 0.4 second delay between attacks,
  so the message cannot be spammed.

- The list of mobs that can eat other mobs has been refactored to be a
  subproc instead of a 255char~ list on one line.

- Mob grab uses #defines for the time it takes to eat something else,
  now.

- Fixed xenomorphs bugging out the grab system, and made sure that fat
  people can't actually eat them because of this.

code/modules/mob/living/carbon/alien/alien_defenses.dm

@@ -49,6 +49,8 @@ In all, this is a lot like the monkey code. /N
 /mob/living/carbon/alien/attack_hand(mob/living/carbon/human/M as mob)
 	if(..())	//to allow surgery to return properly.
 		return 0
+	if(istype(src,/mob/living/carbon/alien/humanoid))
+		return 0 //this is horrible but 100% necessary
 
 	switch(M.a_intent)
 		if("help")

code/modules/mob/living/carbon/alien/humanoid/humanoid.dm

@@ -254,18 +254,7 @@
 			help_shake_act(M)
 
 		if ("grab")
-			if (M == src || anchored)
-				return
-			var/obj/item/weapon/grab/G = new /obj/item/weapon/grab(M, src)
-
-			M.put_in_active_hand(G)
-
-			G.synch()
-
-			LAssailant = M
-
-			playsound(loc, 'sound/weapons/thudswoosh.ogg', 50, 1, -1)
-			visible_message("<span class='warning'>[M] has grabbed [src] passively!</span>")
+			grabbedby(M)
 
 		if ("harm")
 			M.do_attack_animation(src)

code/modules/mob/living/carbon/carbon.dm

@@ -27,34 +27,47 @@ mob/living
 		if(germ_level < GERM_LEVEL_MOVE_CAP && prob(8))
 			germ_level++
 
+#define STOMACH_ATTACK_DELAY 4
+
+/mob/living/carbon/var/last_stomach_attack //defining this here because no one would look in carbon_defines for it
+
 /mob/living/carbon/relaymove(var/mob/user, direction)
 	if(user in src.stomach_contents)
-		if(prob(40))
-			for(var/mob/M in hearers(4, src))
-				if(M.client)
-					M.show_message(text("\red You hear something rumbling inside [src]'s stomach..."), 2)
-			var/obj/item/I = user.get_active_hand()
-			if(I && I.force)
-				var/d = rand(round(I.force / 4), I.force)
-				if(istype(src, /mob/living/carbon/human))
-					var/mob/living/carbon/human/H = src
-					var/obj/item/organ/external/organ = H.get_organ("chest")
-					if (istype(organ))
-						if(organ.take_damage(d, 0))
-							H.UpdateDamageIcon()
-					H.updatehealth()
-				else
-					src.take_organ_damage(d)
-				for(var/mob/M in viewers(user, null))
-					if(M.client)
-						M.show_message(text("\red <B>[user] attacks [src]'s stomach wall with the [I.name]!"), 2)
-				playsound(user.loc, 'sound/effects/attackblob.ogg', 50, 1)
+		if(last_stomach_attack + STOMACH_ATTACK_DELAY > world.time)	return
 
-				if(prob(src.getBruteLoss() - 50))
-					for(var/atom/movable/A in stomach_contents)
-						A.loc = loc
-						stomach_contents.Remove(A)
-					src.gib()
+		last_stomach_attack = world.time
+		for(var/mob/M in hearers(4, src))
+			if(M.client)
+				M.show_message(text("\red You hear something rumbling inside [src]'s stomach..."), 2)
+
+		var/obj/item/I = user.get_active_hand()
+		if(I && I.force)
+			var/d = rand(round(I.force / 4), I.force)
+
+			if(istype(src, /mob/living/carbon/human))
+				var/mob/living/carbon/human/H = src
+				var/obj/item/organ/external/organ = H.get_organ("chest")
+				if (istype(organ))
+					if(organ.take_damage(d, 0))
+						H.UpdateDamageIcon()
+
+				H.updatehealth()
+
+			else
+				src.take_organ_damage(d)
+
+			for(var/mob/M in viewers(user, null))
+				if(M.client)
+					M.show_message(text("\red <B>[user] attacks [src]'s stomach wall with the [I.name]!"), 2)
+			playsound(user.loc, 'sound/effects/attackblob.ogg', 50, 1)
+
+			if(prob(src.getBruteLoss() - 50))
+				for(var/atom/movable/A in stomach_contents)
+					A.loc = loc
+					stomach_contents.Remove(A)
+				src.gib()
+
+#undef STOMACH_ATTACK_DELAY
 
 /mob/living/carbon/gib()
 	for(var/mob/M in src)