No longer use default_wood.png for one side of the bed head and
one side of the bed bottom node.
Add a new texture for the underside of both beds.

Fixes most z-fighting caused by underwater nodeboxes.
Special tiles were for 'new style water' (lowered water level) which was
removed a few years ago.

Fix slabs combining into a cube: Facedir is only set for the cube if it has
paramtype2 = "facedir". This avoids liquid appearing in connected
framed glasslike.

All stair/slab nodes with parent nodes that are rotatable (wood and bricks)
are reverted to not having world-aligned textures, to fix the breakage of
rotated stair/slab appearence in worlds.

Update, and add missing documentation to, game_api.txt.

Fence rail: Only connect to 'group:fence'.
Update map mod README crafting recipe documentation.

Before, it checked if the node name *contained* "stairs:slab_", which could detect
things like "xxxxxstairs:slab_xxxx". Changed the pattern to "^stairs:slab_".

Precisely reduce trees and logs per mapchunk division to compensate.

sfinv:
Move license information to create the missing license.txt file.
Make README consistent with other Minetest Game mods.

player_api:
Add missing texture and sound credits to README.
Update and add extra license information.

default:
Remove credit for 'player_damage.ogg' sound.

Previously, maximum flora density was chosen based on the extremely rare
occurrence of all 8 flowers being at high density at one location. This
caused flora everywhere to spread to an unacceptably high density.

Revert the threshold to 3, which in testing results in a more acceptable
maximum density of 7 flora per 9x9 area.

Replaces 'bush' in snowy grassland.

Move chests code out of nodes.lua and into a new file.
Credit torch code, and chest and torch models in README.txt.
Remove 'torches' mod text from torch.lua.
Minor cleanups in README.txt.

Minor clean up of README.txt, including deletion of credits for removed
torch textures.