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