Loot and dungeon changes

- Dungeons with liquids now generate an extra lower layer
- Water dungeons fill 2 blocks up, submerging the chest
- Lava dungeons should generate the chest on a stone block
- Adjusted loot weights to favor mod items slightly more
- Added config options to enable/disable additions to vanilla loot
tables (chestGenHooks)
- Secret room chests now generate minimum of 3 items instead of only 2
(in addition to bonus heart piece)