Fixes two runtimes in reagent reaction code (caused by my recent changes)

Fixes timer device not showing its countdown overlay when not attached (sprite was removed by accident probably).
Fixes timer/infrared beam/proximity sensor not being usable when freshly spawned because they weren't being processed.

Fixes infrared beam runtime (when the device is deleted the beam itself isn't, causing runtimes when crossing it).

code/modules/assembly/timer.dm

@@ -10,6 +10,10 @@
 	var/time = 5
 
 
+/obj/item/device/assembly/timer/New()
+	..()
+	SSobj.processing |= src
+
 /obj/item/device/assembly/timer/describe()
 	if(timing)
 		return "The timer is counting down from [time]!"
@@ -20,7 +24,7 @@
 	if(!..())	return 0//Cooldown check
 	timing = !timing
 	update_icon()
-	return 0
+	return 1
 
 
 /obj/item/device/assembly/timer/toggle_secure()
@@ -42,17 +46,16 @@
 	cooldown = 2
 	spawn(10)
 		process_cooldown()
-	return
+	update_icon()
 
 
 /obj/item/device/assembly/timer/process()
-	if(timing && (time > 0))
+	if(timing)
 		time--
-	if(timing && time <= 0)
-		timing = 0
-		timer_end()
-		time = initial(time)
-	return
+		if(time <= 0)
+			timing = 0
+			timer_end()
+			time = initial(time)
 
 
 /obj/item/device/assembly/timer/update_icon()
@@ -63,7 +66,6 @@
 		attached_overlays += "timer_timing"
 	if(holder)
 		holder.update_icon()
-	return
 
 
 /obj/item/device/assembly/timer/interact(mob/user)//TODO: Have this use the wires
@@ -76,7 +78,6 @@
 		var/datum/browser/popup = new(user, "timer", name)
 		popup.set_content(dat)
 		popup.open()
-		return
 
 
 /obj/item/device/assembly/timer/Topic(href, href_list)
@@ -107,4 +108,3 @@
 	if(usr)
 		attack_self(usr)
 
-	return