Also fixes long-standing accuracy issue due to unknown wider
object count not being incremented.

Unless I'm mistaken, the chunk of code I'm moving there is potentially
executed hundreds of times inside the loop to get the exact same result
every time

Revert patch 58f036ad that causes object duplication (which tried to fix objects getting hidden from client) and fix the original problem correctly. This fixes the second distinct object duplication bug.

The real problem was that MapBlocks were not activated before getting sent to the client

Change large amount of objects to be configurable via a setting in minetest.conf (max_objects_per_block).

Play player_damage.ogg when recieving damage and additionally play player_falling_damage.ogg when recieving falling damage

Now Environment::clearAllObjects() unloads unused blocks in an interval
defined by max_clearobjects_extra_loaded_blocks (default 4096).

On the lua side, notably minetest.env:<function>(<args>) should now
be replaced by minetest.<function>(<args>).
The old way is and will stay supported for a long time.

Also:
Update and clean up lua_api.txt (by celeron55)
Move EnvRef to lua and remove add_rat and add_firefly (by kahrl)
Add separate src/util/CMakeLists.txt, other minor fixes (by kahrl)