This removes the group overrides for dirt, dirt_with_grass and dirt_with_dry_grass which aren't needed and interfere with new grass spreading changes: https://github.com/minetest/minetest_game/pull/1286

Commit originally by PilzAdam.
Settings appear in advanced settings menu.

The collision box still extended into a neighbouring empty node, causing
falling node objects to collide but not transform back into normal nodes.
Completes the fix started in a previous similar commit.

From PixelBOX2 texture pack.
Brightness increased for 'snow' and 'snow side'.

Combine slabs if identical based on orientations using a simple lookup
table if the nodes are identical.

Otherwise relies on place_node() to place the node, which properly
handles rotation compared to adjacent nodes already, and can orient
based on look_dir as well.

Initial slabs placed are oriented based on (1) the orientation of
the pointed "face" (assumes nodes are cubic, of course), and uses
the player look direction to orient the node n/e/w/s if the slab
is horizontal or upside-down. If placed against a vertical face,
the slab is placed against the face without rotation around the axis
perpendicular to that vertical face. This allows upside down placement
and vertical placement without screwdriver.

If a slab is placed on top of an upside down slab, or below a normally
placed slab, the rotation is inverted so that no "floating" slab
is created.

Largely based on kilbith's #807 PR. Slab combining and place_node()
usage by sofar.

Since this relies entirely on `on_place` mechanics, this fails to
combine slabs into a plain node if the space *above* is occupied.
This is unavoidable due to the fact that on_place() happens after
the checks required to see if pointed_thing.above is empty or not.

When a player dies on ladders or rope then a space can not be found at or
above player, so this change looks around player for a space to place bones.

I've rewritten this to use connected nodeboxes, but with a caveat. In
order to make flat nodes look better, I'm keeping one non-connected
pane that is flat around to convert flat sections to the flat nodes
instead of connected, as these look better and are easier to work
with. Once more sides are needed we convert the panes on the fly to
connected nodes and recalculate the shape.

We don't paint any of the half-panes that the previous generation of
xpanes did. There's no need and it's harder to work with. Updating the
nodes also seems more natural and placement and removal works straight
forward.

The conversion of old panes relies on an LBM, and does a reasonable
conversion job, but it's not exact, since the panes behave slightly
different now.

The game API documentation was wrong to begin with. We discard param
nr. 2 of the API entirely, and correct the tile usage text.

Relicense WTFPL media to CC BY-SA 3.0.
Various corrections and edits.

Add license.txt files.
Update and improve README.txt files.
Corrections to part 1.

Part 1: All mods except default and xpanes.
Add license.txt files.
Add missing README.txt files.
Check and update copyright years for all contributors.
Improve text format and make more consistent.

Retain definitions for node groups to support mods.
Burn time is unchanged for applewood, and increases in the order:
aspen, pine, apple, acacia, jungle which is also the order of wood
colour darkness.

Indicate in the infotext when a furnace has filled up `dst` but still
has fuel. The info text shows the item as 100% with added "(output
full)" text, indicating that while it can cook the item, there is no
place for it in the `dst`. Emptying the `dst` should make the item
cook immediately and furnace resume normal operation.

Dig time is modified according to difference (leveldiff) between tool
'maxlevel' and node 'level'. Digtime is divided by the larger of leveldiff
and 1. In creative mode, where the hand is redefined to have maxlevel 3,
this results in higher level nodes taking significantly longer to break.

Now, to speed up digging, hand 'maxlevel' and 'digtime' have been
increased such that nodes of differing levels have an insignificant
effect on digtime. Dig time for all nodes is now identical to that of, for
example, dirt nodes.

Make the softer woods, pine and aspen, 'flammable = 3'.
Correct inconsistent flammability of wood and stairs in relation
to all other solid wood nodes in MTGame.
Make the the softer woods, pine and aspen, 'choppy = 3'.

Use 'find node near' instead of 'find nodes in area'

With thanks to contributor tenplus1
Remove leaf cache and globalstep accumulator limiter
Use 'pos' instead of 'p0'
Remove non-essential 'group:liquid' from 'neighbors'
Increase chance value to 10 to compensate for disabled cache
Disable 'catch-up' to avoid the ABM often becoming 10 times more
intensive
Remove use of 'do preserve' bool, instead simply 'return'
Remove unnecessary checks for 'd' and 'd == 0'
Don't 'get' n0, use already present 'node' instead
Swap order two conditionals so that the one most likely is first

Useful for searches and the mod profiler.

Allows walking in, and prevents being trapped in, 2 node high spaces.
Simulates player's feet sinking into snow.
Easier jumping up onto nodes with snow.

This replaces the hardcoded 99 item limit and instead uses the
get_stack_max() limit for each item.

Other screwdriver mods, or mods that cause rotation, might operate without the screwdriver mod loaded and have `screwdriver.disallow` unavailable.
This allows nodes to default to full-disallow rather than full-rotation in such a situation.

Keep other axis' disabled to prevent the hidden placeholder node to become irremovable to players.

This fixes the TNT bug that can crash game when blowing up a container
which holds huge stacks above the norm... e.g. give yourself 65535 snow,
place in chest, blow up, stalled!

Previously, the collision box extended into an empty node, causing
falling node objects to land on the open gate but not transform
back into normal nodes. Now fallng node objects will fall through and
either side of the end of the open gate and transform back.

Fix crash when doors are placed under unknown nodes.
Share a can_dig among doors, that does not crash on nil-player.
Only set can_dig if we actually protect the door.

Add mouth, remove jaw shadow, shade eyesockets.
Darker shading for spine and rotate texture using ^[transform2
instead of inverting texture.
Use 'node sound gravel defaults' for sounds.

Add a global 'intersects protection' function to functions.lua for
checking if a specified volume intersects with a protected volume.
A 3D lattice of points are checked with an adjustable interval.
Add a global 'sapling on place' function to avoid duplicated code in
nodes.lua.

Add 'bones_mode' setting to minetest.conf -> Modes: bones, drop, keep
Remove table 'bones'
Add minetest.conf.example description
Remove protection check from may_replace

Add 'record_protection_violation()'