Remove unused variables and do some whitespace fixes

src/abms.lua

@@ -4,7 +4,7 @@ minetest.register_abm({
 	nodenames = {"default:dirt_with_snow"},
 	interval = 2,
 	chance = 20,
-	action = function(pos, node)
+	action = function(pos)
 		local name = minetest.get_node({x=pos.x, y=pos.y+1, z=pos.z}).name
 		local nodedef = minetest.registered_nodes[name]
 		if name ~= "ignore"
@@ -144,7 +144,7 @@ minetest.register_abm({
 	nodenames = {"snow:sapling_pine"},
 	interval = 10,
 	chance = 50,
-	action = function(pos, node)
+	action = function(pos)
 
 -- Check if there is enough vertical-space for the sapling to grow without
 -- hitting anything else.  ~ LazyJ, 2014_04_10
@@ -177,7 +177,7 @@ minetest.register_abm({
 	nodenames = {"snow:xmas_tree"},
 	interval = 10,
 	chance = 50,
-	action = function(pos, node)
+	action = function(pos)
 
 		-- 'If' there is air in each of the 8 nodes dirctly above the sapling,... ~LazyJ
 		for i = 1,8 do

src/falling_snow.lua

@@ -1,6 +1,6 @@
 -- Parameters
 
-function snow_fall(pos, player, animate)
+function snow_fall(pos)
 	local ground_y = nil
 	for y=pos.y+10,pos.y+20,1 do
 		local n = minetest.get_node({x=pos.x,y=y,z=pos.z}).name
@@ -184,7 +184,7 @@ if snow.enable_snowfall then
 									}, true)
 						end
 
-						for flake = 1, FLAKES do
+						for _ = 1, FLAKES do
 
 							x, y, z = pposx - 24 + math.random(0, 48), pposy + 12, pposz - 24 + math.random(0, 48)
 

src/mapgen_v6.lua

@@ -577,7 +577,7 @@ local biome_strings = {
 	{"snowy", "plain", "alpine", "normal", "normal"},
 	{"cool", "icebergs", "icesheet", "icecave", "icehole"}
 }
-function biome_to_string(num,num2)
+function biome_to_string(num)
 	local biome = biome_strings[1][num] or "unknown "..num
 	return biome
 end

src/sled.lua

@@ -156,7 +156,7 @@ function sled:on_rightclick(player)
 	on_sled_click(self, player)
 end
 
-function sled:on_activate(staticdata, dtime_s)
+function sled:on_activate(staticdata)
 	self.object:set_armor_groups({immortal=1})
 	self.object:setacceleration({x=0, y=-10, z=0})
 	if staticdata then