The real slips rewrite (#22490)

* Fix a bug in forceMove

Don't call Exited/Entered if the loc is the same

* Added forced_movement

* Remove usages comment

Fixed a parameters bug

* Refactor slips

* Refactors meathook

* Negative check

* Shittier syntax, more performance

* Seperation of src and args

* Sanity check

Because you know someone will fuck it up

* X to Y is inclusive

* Bettter diagonals

* Remove unused var

* Better suggestion

* This was never used, why was it here?

* Arg prefixing...

* Better cleanup

* Do not touch the self managing var

* Cleanup

* More cleanup

* Missed 2

* Added callbacks

* Fix ice again

* Sanity checks

* Applied to larva/attack_hulk

* Fix the chain's usage

* LDFJAHDJKAGFHLJKDSAGHJKLSDAGBLKJADGFHKLJADGNLKAMDFNBJK:ANFDJKLADSNLSJKDFHNASFADSFLK:AJFL:KASJFKLASJF:LAJSF:LKJASKFMSALKF

code/modules/mob/living/carbon/alien/larva/larva_defense.dm

@@ -22,10 +22,7 @@
 	if(user.a_intent == INTENT_HARM)
 		..(user, 1)
 		adjustBruteLoss(5 + rand(1,9))
-		spawn()
-			step_away(src,user,15)
-			sleep(1)
-			step_away(src,user,15)
+		new /datum/forced_movement(src, get_step_away(user,src, 30), 1)
 		return 1
 
 /mob/living/carbon/alien/larva/do_attack_animation(atom/A, visual_effect_icon, obj/item/used_item, no_effect, end_pixel_y)

code/modules/mob/living/living.dm

@@ -519,7 +519,7 @@
 				if (AM.density && AM.anchored)
 					pressure_resistance_prob_delta -= 20
 					break
-	if(!slipping)
+	if(!force_moving)
 		..(pressure_difference, direction, pressure_resistance_prob_delta)
 
 /mob/living/verb/resist()

code/modules/mob/living/living_defines.dm

@@ -74,6 +74,4 @@
 
 	var/list/status_effects //a list of all status effects the mob has
 
-	var/slipping = FALSE
-
 	var/list/implants = null

code/modules/mob/mob_movement.dm

@@ -127,10 +127,10 @@
 		return 0
 	if(moving)
 		return 0
+	if(mob.force_moving)
+		return 0
 	if(isliving(mob))
 		var/mob/living/L = mob
-		if(L.slipping)
-			return 0
 		if(L.incorporeal_move)	//Move though walls
 			Process_Incorpmove(direct)
 			return 0