Implement global loot system Fixes #619

This should allow us to emulate lives global tables

The options available to filter tables are min_level, max_level, race,
rare, raid, race, class, bodytype, and zone.

race, class, bodytype, and zone are a pipe | separated list of IDs

zone/zonedump.h

@@ -141,6 +141,8 @@ struct NPCType
 	bool	ignore_despawn;
 	bool	show_name; // should default on
 	bool	untargetable;
+	bool	skip_global_loot;
+	bool	rare_spawn;
 };
 
 namespace player_lootitem {