Z-Lights Mk 2 (#4383)

changes:
Bidirectional source Z-lights have been reverted to single-direction in favor of corner z-bleed.
Z-mimic turfs will now average their light level with their mimiced turf to better approximate Z-lighting.
Openspaces have been made significantly less dark.
Corners no longer incorrectly always take the instant update pathway.
MultiZ helpers are now macros.
More things now properly respect area dynamic lighting settings.

code/modules/hydroponics/seed.dm

@@ -292,7 +292,7 @@
 
 	// Handle light requirements.
 	if(!light_supplied)
-		if (current_turf.dynamic_lighting)
+		if (TURF_IS_DYNAMICALLY_LIT(current_turf))
 			light_supplied = current_turf.get_lumcount(0, 3) * 10
 		else
 			light_supplied = 5

code/modules/hydroponics/trays/tray.dm

@@ -647,10 +647,11 @@
 			light_string = "that the internal lights are set to [tray_light] lumens"
 		else
 			var/light_available
-			if(T.dynamic_lighting)
+			if(TURF_IS_DYNAMICALLY_LIT(T))
 				light_available = T.get_lumcount(0, 3) * 10
 			else
-				light_available =  5
+				light_available = 5
+
 			light_string = "a light level of [light_available] lumens"
 
 		usr << "The tray's sensor suite is reporting [light_string] and a temperature of [environment.temperature]K."