Fix crash in 'mcl_spawn' in v6,flat,singlenode mapgens; and fix mobs despawning when attacking/following players.

mods/ENTITIES/mcl_mobs/api.lua

@@ -3604,7 +3604,9 @@ local mob_step = function(self, dtime)
 	-- Despawning: when lifetimer expires, remove mob
 	if remove_far
 	and self.can_despawn == true
-	and ((not self.nametag) or (self.nametag == "")) then
+	and ((not self.nametag) or (self.nametag == ""))
+	and self.state ~= "attack"
+	and self.following == nil then
 
 		self.lifetimer = self.lifetimer - dtime
 		if self.despawn_immediately or self.lifetimer <= 0 then

mods/PLAYER/mcl_spawn/init.lua

@@ -425,7 +425,7 @@ end
 minetest.register_on_respawnplayer(mcl_spawn.spawn)
 
 function mcl_spawn.shadow_worker()
-	if #biome_ids < 1 then
+	if #biome_ids > 1 then
 		for _, biome_name in pairs(biomes_white_list) do
 			table.insert(biome_ids, minetest.get_biome_id(biome_name))
 		end