Nether Tweaks

Nether Tweaks adds a couple of options for customizing Nether-related structures. ## Fortress Height Adds a configurable y-offset for Nether Fortress placement. You might want to do this if you have changed the height of the Nether or made more extensive changes to Nether worldgen. ## Portal Restrictions Allows you to disable lighting of Nether portals outside of the bounding box of a configurable list of structures. One possible use would be to only allow portals to be lit where a ruined portal already exists. There is also an option to remove these restrictions once a portal has been successfully lit.