Fullscreen overlay rework, full-black unconsciousness overlay, overlay fadeout animations + more. (#10053)

Ported the clickcatcher from tg/bay. You can now click black spots to turn. Isn't that handy, especially with vision cones.

    Reworked fullscreen overlays into an easier and better system, courtesy of PsiOmegaDelta.

    Similiarly, added fadeout animations to all pain overlays, plus unconsciousness.

    Fixed the vampire frenzy overlay never showing.

    Unconsciousness is now FULL darkness.

    Flashing mobs is now an inbuilt proc.

code/modules/organs/pain.dm

@@ -1,9 +1,7 @@
-/mob/proc/flash_pain()
-	flick("pain", pain)
-
-/mob/living/carbon/human/flash_pain()
-	if(can_feel_pain())
-		flick("pain", pain)
+/mob/proc/flash_pain(var/target)
+	if(pain)
+		animate(pain, alpha = target, time = 15, easing = ELASTIC_EASING)
+		animate(pain, alpha = 0, time = 20)
 
 mob/var/list/pain_stored = list()
 mob/var/last_pain_message = ""
@@ -25,6 +23,8 @@ mob/var/next_pain_time = 0
 		else
 			affecting.add_pain(Ceiling(power/2))
 
+	flash_pain(min(round(2*power)+55, 255))
+
 	// Anti message spam checks
 	if(force || (message != last_pain_message) || (world.time >= next_pain_time))
 		last_pain_message = message
@@ -32,13 +32,10 @@ mob/var/next_pain_time = 0
 			flash_strong_pain()
 			to_chat(src, "<span class='danger'><font size=3>[message]</font></span>")
 		else if(power >= 70)
-			flash_pain()
 			to_chat(src, "<span class='danger'><font size=3>[message]</font></span>")
 		else if(power >= 40)
-			flash_pain()
 			to_chat(src, "<span class='danger'><font size=2>[message]</font></span>")
 		else if(power >= 10)
-			flash_weak_pain()
 			to_chat(src, "<span class='danger'>[message]</span>")
 		else
 			to_chat(src, "<span class='warning'>[message]</span>")