Improvements to get_all_craft_recipes (see api doc)

Spawn single particles or make use of ParticleSpawner for many randomly spawned particles.
Accessible in Lua using minetest.spawn_particle and minetest.add_particlespawner.
Increase Protocol Version to 17.

Conflicts:
	src/clientserver.h

Fixed also game bug drawing dragged item behind fields, buttons etc.

Nodes in this group will be dropped as items if the node under them or the node in the wallmounted direction is not walkable.

Scripts can call minetest.register_on_shutdown() to register a
shutdown hook.

Document that minetest.register_on_shutdown() callbacks may not be run

If the server crashes, it is unlikely that callbacks registered using
minetest.register_on_shutdown() will be called.

RealBadAngel's patch which allows the lua api to read pressed player keys. This should make it possible to change the player's animation based on what he is doing

Correct lua api version number

Always update animations and attachments after the entity is added to scene client side. Fixes animations not being applied in client initialization for some reason. Attachments should be re-tested now just to be safe.

Fix a segmentation fault caused by reaching materials that didn't exist in a loop for setting texture

No longer hide players who are dead. With models, a death animation should be used instead

Some changes requested by celeron55

Rename a lot of things in the code, and use better lua api function names

Minor code corrections

Bump protocol version up, since the models / animations / attachments code creates new client<->server messages

Update attachments at the ending of the addToScene function for parents. And with this... *drum roll* Client-side attachments are at last functional and stick visibly.

Fix the last segmentation fault (apparently). So far attachments seem to be fully functional, although removing the parent causes children to go to origin 0,0,0 and possibly still cause such a fault (though this should already be addressed)

Fix a bug in falling code where entities get stuck

Also check if the parent has been removed server-side, and detach the child if so. Fixes children going to origin 0,0,0 when their parent is removed.

Unset all attachment properties when permanently detaching (on both the client and server). Also store less data we don't need

Create a separate function for detaching, and also update lua api documentation

When a child is detached, update its position from the server to clients. This WILL cause it to get positioned slightly differently client side, as the server attachment system only copies parent origin and knows not about mesh / bone transformation. This prevents different clients seeing the object detached in different spots which is most correct

Update the position of attached players to clients. An attached player will see himself move, but this is currently VERY ugly and laggy as it is done by the server (it probably must stay this way too)

Use a different approach for locally attached players. This allows for smooth positio transitions to work, as well at the player turning around freely. Still buggy however

Framework for the attachment system, new object property which allows changing the color and alpha of mesh materials

New object property which allows changing the color and alpha of mesh materials. Due to the current lighting systems it doesn't work yet, but the full implementation is there

Framework for the attachment system, with no actual functionality yet

Send bone and player object to the setAttachment function in content_sao.cpp, but we need a way to translate it there and send it to the client

I will also want position and rotation offsets to be possible to apply to attachments

Network object ID from server to client. This will be used to identify the parent client-side and know what to attach to