Separated loot config settings

Created a separate category for loot properties so that they're not lost
among all the Limbo flags.
Fixed bug in DDLoot, delayed loot generation

Changed DDLoot to use the correct item IDs when adding DD items to
chests. Moved loot chest registration from init() to postInit() in the
hopes that we'll be able to catch the loot of other mods that also hook
into Vanilla chests.