Porting movespeed modification system updates.

code/modules/surgery/organs/augments_chest.dm

@@ -129,7 +129,7 @@
 	var/datum/effect_system/trail_follow/ion/ion_trail
 
 /obj/item/organ/cyberimp/chest/thrusters/Insert(mob/living/carbon/M, special = 0)
-	..()
+	. = ..()
 	if(!ion_trail)
 		ion_trail = new
 	ion_trail.set_up(M)
@@ -151,10 +151,14 @@
 		on = TRUE
 		if(allow_thrust(0.01))
 			ion_trail.start()
+			RegisterSignal(owner, COMSIG_MOVABLE_MOVED, .proc/move_react)
+			owner.add_movespeed_modifier(MOVESPEED_ID_CYBER_THRUSTER, priority=100, multiplicative_slowdown=-2, movetypes=FLOATING, conflict=MOVE_CONFLICT_JETPACK)
 			if(!silent)
 				to_chat(owner, "<span class='notice'>You turn your thrusters set on.</span>")
 	else
 		ion_trail.stop()
+		UnregisterSignal(owner, COMSIG_MOVABLE_MOVED)
+		owner.remove_movespeed_modifier(MOVESPEED_ID_CYBER_THRUSTER)
 		if(!silent)
 			to_chat(owner, "<span class='notice'>You turn your thrusters set off.</span>")
 		on = FALSE
@@ -169,6 +173,9 @@
 		var/datum/action/A = X
 		A.UpdateButtonIcon()
 
+/obj/item/organ/cyberimp/chest/thrusters/proc/move_react()
+	allow_thrust(0.01)
+
 /obj/item/organ/cyberimp/chest/thrusters/proc/allow_thrust(num)
 	if(!on || !owner)
 		return 0