* Initial stab at volcano mapgen
* Make caldera conical, randomized size a bit
* remove grass from underwater soil
* add snow, fix some errors in mountain shape calculations
* improved soil and snow generation, more efficient mapgen
* add some configuration for volcanos, and a find volcanoes command for debugging
* enhance findvolcano, chunk sizes limited to multiples of mapblocks
* more volcano options, also add soil cooking
* update readme and screenshot
* cosmetic tweaks, slight change to default slope range
* fixed the mapgen v7 glitch via a horrible hack :(
* fix the need-to-make-changes test
* use biome-defined material to decorate slopes
* apparently set_lighting and calc_lighting are only supposed to be called on mapgen voxelmanipulators
* add magma chambers at the base of the volcano pipe
* fixes to large-scale grid calculations
* remove a line I added for debugging purposes
* bringing back configurable limits now that the bug's been fixed for six months
* generalizing the heating/cooling ABM
* actually turn the cooling material into the targeted material.
* Revert "actually turn the cooling material into the targeted material."
This reverts commit 508e10acc7c3871cc56fb8347e7931e5595b5f54.
* Fix cooling target node type for real
* very strange, abms don't seem to be updating node groups somehow.
* Workaround for Minetest issue #7864
* using minetest.after proved unreliable, trying different approach
* remove the lava cutoff setting, no longer needed now that veins are fixed
* improve findvolcano command
* using the same solution for v7 mapgen bug as for the lava crash
This is still not 100% reliable, but it's still better than the post-gen patching.
* fix randomization of lava depth
* remove debugging
* extinct volcano lava depth wasn't working right either
