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.

Moist rainforest plant litter.
Textures by npx.

Utilizes several new features allowing the description of an item to be changed using the `description` meta key. This also moves keys from using the old single-value itemstack metadata system to the new node-like metadata system.

Return to previous parameters interval = 1, chance = 2.
Compensates for the increase in default active block radius.
Large amounts of lava cooling at once is known to overload sound
creation, producing error messages.

As part of the original plan for a new lightcurve.

With the old lightcurve lights were so dim all light sources had light
source level 13 or 14 to compensate, resulting in almost no difference
between torchlight and a maximum brightness light.

The new lightcurve makes all light sources effectively much brighter by
spreading visually-bright light further, torches are now slightly too
bright. So now we can reduce the light source level of torches while
actually making them effectively brighter than with the old lightcurve.
This also creates a desirable difference between torchlight and a
maximum-brightness light source.

This implements a node-timer based leafdecay mechanism, and exposes
an API to use it in mods.

The API is documented in game_api.txt.

`default.register_leafdecay(leafdecaydef)`

`leafdecaydef` is a table, with following members:
{
	trunks = { "default:tree"}, -- nodes considered trunks
	leaves = { "default:leaves", "default:apple"}, -- nodes considered leaves
	radius = 3, -- activates leafdecay this far from the trunk
}

The algorithm will drop `leaves` items in the area if no `trunks` are found
in the `trunk_radius` sized area around the position of the leaf. If a node
listed in `leaves` has a group `leafdecay_drop > 0`, then the item is dropped,
otherwise the item is removed but not dropped.

The algorithm also implements a value `default.leafdecay_speed` (default
15) which can be modified to increase or decrease of the leaf decay. The
algorithm will vary the actual speed a bit to introduce randomness.

Leaf decay is randomized by 0.1 seconds to reduce the chance that
decay happens many times on the same second interval. This requires
nodetimer_interval to be set to values lower than 1.0 to have an
effect.

The leaves will decay between 2 and 10 seconds after digging the trunk,
and happen at non-integer second intervals.

-- The API was added by sofar.

* rename to default.can_interact_with_node()
* pass pos instead of meta
* change order of arguments

Plantlike drawtype no longer applies 'visual scale' twice, so now we
use the actual scale factor desired.
Remove unnecessary 'visual_scale = 1.0' lines.

Avoid z-fighting visible from below.
Raise the nodebox base 1/64th of a node.

Light level 14 to be able to grow plants.
3 returned from crafting with 1 glass node, 3 mese crystals and 1
wood plank.
Seamlessly placable on appletree wood fence posts.

Using @paramat's formula.

Now that biomes are being specified for blob ores we need a separate
set of blob ore registrations for mgv6 which has no Biome API biomes
defined.
Various minor improvements to mapgen.lua.

Use the 'snowy' group in the 'is snow nearby' function instead of
default nodes. Often snow nodes are not from the default mod.

Now that the missing 'default_dig_snappy' sound has been added we can
remove the dirt dig sound from the table. All nodes that use the
leaves defaults table have group 'snappy' so 'default_dig_snappy' now
becomes their default dig sound.

Removes the "iCCP: known incorrect sRGB profile" error messages on the
console when starting minetest_game by stripping offending color profiles.

This reverts commit 5e4a6e8a, and
             commit 60cf3f85.

The original door API rewrite I posted had all rotation disabled using
the correct on_rotate() handler returning `false`. Two subsequent
changes attempting first to enable simple rotation and second disabling
that again changed the callback handler to a boolean `false`, which
is incorrect use in the screwdriver API, and actually allows rotation.

The proper way to disable rotation for facedir nodes it to use a full
callback handler that does `return false`.

TNT removes flammable nodes from the destruction radius and should
remove flames within it too because they lose their fuel and would
be removed by ABM later anyway.

Create a simple triplet table (src1, src2, dst) for all the dye
recipes and group them logically, with a bit of explanation where
they actually come from.

This prunes a lot of recipes from the list, but the old list had a
ton of combinations that did not make any sense, as well as recipes
that were just gross approximations and duplicates, mixing the same
color with itself just to get the same color back, which just wastes
packets at logon.

The list has been checked to allow all colors created from the basic
dyes (flowers+coal) so that all colors can be crafted.

Craft 4 default:sand to default:sandstone.

Previously, 4 group:sand was craftable to sandstone and sandstone was
craftable back into default:sand, allowing silver and desert sands to
be converted into incorrect colour sandstone and yellow sand.

Copy-paste and only remove form-feed characters.

Added as a new mod as it doesn't fit anywhere else.

This is a game play change, so it better suited to
Minetest Game rather than builtin

Fixes #857

Fixes #1364

Require only 1 mese crystal instead of 3.
To make farming in dark locations easier.
To reduce and balance recipe ore cost.