Adds a magma oceans region to the nether outside the existing nether caverns, which can be reached via tunnels.
Other misc changes:
* chatcomment nether_whereami, a debug aid for knowing which perlin-noise region you are in
* Nether ores no longer obtainable on the ceiling
* Move crafts into crafts.lua
* Add steam to lava cooling, and play bubbling lava upon death by lava
* Add cracked netherbrick
a decorative node which can only be obtained from dungeons or structures
I encourage someone to improve or replace the cracked netherbrick texture. For copyright purposes it's currently a derivative work (by me, 2020) from nether_brick.png, which is licensed under CC BY-SA 3.0 by PilzAdam, so it can fall under the "All other media" PilzAdam's credit in readme.md rather than need its own entry.
* textures for new tool items
* axe, shovel, pick, sword based on nether
* run also tools.lua
* Textture for Compressed Netherbrick
* new node "Compressed Netherbrick"
* define how to craft "Compressed Netherbrick"
* change recipe for NetherLump and remove old node
* Delete nether_nether_compressed.png
