* Server::overrideDayNightRatio doesn't require to return bool
There is no sense to sending null player, the caller should send a valid object
* Server::init: make private & cleanup
This function is always called before start() and loads some variables which can be loaded in constructor directly.
Make it private and call it directly in start
* Split Server inventory responsibility to a dedicated object
This splits permit to found various historical issues:
* duplicate lookups on player connection
* sending inventory to non related player when a player connects
* non friendly lookups on detached inventories ownership
This reduce the detached inventory complexity and also increased the
lookup performance in a quite interesting way for servers with thousands
of inventories.
* Modernize lua read (part 2 & 3): C++ templating assurance
Implement the boolean reader
Implement the string reader
Also remove unused & unimplemented script_error_handler
Add a reader with default value
This unifies the settings APIs.
This also unifies the sync and async registration APIs, since the async
registration API did not support adding non-functions to the API table.
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)
