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()'

Removing the node above was an error and is unnecessary

This makes register_trapdoor act the same as the register_door.
If `name` isn't prefixed, it will be prefixed with "doors:".

Nyancats are independent in the default mod. Nothing else uses them or
their code. Separating it into a separate mod makes it easier for
subgames to remove them. It also makes it easier for a mod to depend
on nyancats, as lots of subgames don't have them.

Default/mapgen.lua: Register biomes, ores and decorations in
singlenode mapgen. These were never disabled anyway because
singlenode was removed from the world creation menu.

* Unused variables
* Unused values (assigned to variables, but overwritten before use)
* Defining already defined variables instead of reassigning to them.

No longer require night to be skipped for resawn position to be saved
Remove constant beds.read_spawns() calls when a player joins as this
is only required once

Instead of using voxelmanip use 'find nodes in area' instead

Remove spaces inside curly brackets
Split lines over 90 columns