Added Pollution Grading

config/pollution_grading.lua

@@ -0,0 +1,7 @@
+-- This controls how pollution is viewed on the map
+return {
+    reference_point = {x=0,y=0}, -- where pollution is read from
+    max_scalar = 0.5, -- the scale between true max and max
+    min_scalar = 0.17, -- the scale between the lowest max and min
+    update_delay = 15 -- time in minutes between view updates
+}