Update readme.txt with new TNT crafting recipe.

Without this patch, any fire created(placed) by tnt explosions
will remain forever on the map.

Completes a forgotten update in 9d3a5263

This should be fairly cheap and pops off items if needed.

The table was generated using the old code. A table lookup
should be faster than lots of math and branches.

Allows us to drop `nextrange()` as well.

Allows rotating things like signs and torches. Axis rotation
rotates over all 6 faces, face rotation flips upside down to
flat on floor only, and of course in the 4 horizontal directions.

Made the code a bit more modular to account for different rotation
schemes. Should be easier to extend from here on to other needs,
and the functions can be reused by other mods for convenience.

Usage and tool break sounds were played at 'pointed_thing.above' which
can be nil if not pointing at anything or at an entity. This caused
sounds to be played to all players on a server non-positionally.

Fallback to player pos for sounds if 'pointed_thing.above' is nil.

Replace 'pt' variable with 'pointed_thing' in 'register_tool'.

Currently jungletrees and junglegrass use sidelen 80 for simplicity,
but this results in a more uneven distribution of decorations. A more
even distribution helps keep rainforest darker with a more unbroken
canopy.
This is also more consistent. 80 is based on the default mapchunk
size, all other decorations use sidelen 16 or smaller to divide into
any mapchunk size.

Denser jungletree for darker rainforest:
Highest 'jungletree' nodes now prob 255.
Add a 5th lower branch layer.
Increase lower branch layer y-slice prob to 191.

Aspen:
Extend trunk upwards by 1 node to reduce leafdecay radius to 2.

Pine:
Make lower trunk 1 node longer so that lowest branches are more often
higher off the ground, also to make pines taller.

Appletree:
Make 2 opposite branches prob 255, the other 2 prob 127, to avoid
trees with 1 or 0 branches. Therefore also add random rotation.

Increase to 5 ladders from 7 sticks.
More generous to help with vertical travel.

Divide the log core volume of 14 * 14 * 16 cubic pixels by the volume of
a ladder node with two 2 * 2 * 16 side pieces and four 2 * 1 * 16 rungs
(cut down to length 14), to get 12.25 ladders per log.
The recipe of 7 stick items is 7 / 16 = 0.4375 logs.
Ladders per 7 stick items = 0.4375 * 12.25 = 5.36.

Thank you to @ForbiddenJ for finding cause of the issue.

If 'node_box' is nil 'node_box.type' causes a crash.

Add desert and silver sand-related blocks, and stairs.

Also fixes the failing travis checks.

Utilizes the new key-meta (as with nodes) and the ability to set the description of an itemstack with the `description` meta key. Includes code to convert old metadata to new key-meta.

- beds
- boats
- carts
- key/skeleton key
- seeds

All these had on_place handlers that did not allow nodes with
an on_rightclick() handler to be used first (if not using
sneak). This code is taken from the torches mod and applied
everywhere.

This allows all these items to e.g. be inserted into the `frame`
mod's item frames.