Improve heavy snow performance, add pedology support, add documentation

abms/pedology.lua

@@ -0,0 +1,28 @@
+if not regional_weather.settings.pedology
+or not minetest.get_modpath("pedology")
+then return end
+
+climate_api.register_abm({
+	label			= "wetten or dry pedology nodes",
+	nodenames = { "group:sucky" },
+	neighbors = { "air" },
+	interval	= 25,
+	chance		= 30,
+	catch_up	= false,
+
+	conditions	= {
+		min_height		= regional_weather.settings.min_height,
+		max_height		= regional_weather.settings.max_height,
+		min_heat			= 25,
+		min_light			= 15
+	},
+
+	action = function (pos, node, env)
+		local wetness = minetest.get_item_group(node.name, "wet") or 0
+		if wetness < 2 and env.humidity > 55 then
+			pedology.wetten(pos)
+		elseif wetness > 0 and wetness < 3 and env.humidity < 40 then
+			pedology.dry(pos)
+		end
+	end
+})