The bar is only drawn when the user will notice a change, which prevents time overheads that this commit would cause, resulting from useless draws.

Rename some packet and handlers to <packet>_Legacy name for compat layer between new network changes and old network clients

Also change bzero to memset. bzero doesn't work on windows

For usages of assert() that are meant to persist in Release builds (when NDEBUG is defined), replace those usages with persistent alternatives

Performance improvement: Use std::list instead of std::vector for request_media, Server::getModNames, Environment::m_simple_objects.
* Also remove unused Server::m_modspaths

NetworkPacket.cpp:
* Remove some deprecated functions, we must use streaming interface
* m_data converted from u8* to std::vector<u8>
* Add an exporter to forge packet to Connection object
* implement operator << std::wstring. n
* implement operator << std::string
* dynamic resize when write packet content.
* fix string writing and performances.
* create ServerCommandFactory, used by client to get useful informations about packet processing (sending).
  * Reliability
  * Transmit channel
* Implement putRawString for some ugly char (_INIT packet), and use it.
* Many packet read and write migrated
* Implement oldForgePacket to interface writing with current connection
* fix U8/char/bool writing
* fix string writing and performances.
* add some missing functions
* Use v3s16 read instead of reading x,y,z separately
* Add irr::video::SColor support into packets
* Add some missing handlers
* Add a template function to increase offset
* Throw a serialization error on packet reading (must be improved)

PacketFactories:
* Create ServerCommandFactory, used by client to get useful informations about packet processing (sending).
* Create ClientCommandFactory, used by server to get useful informations about packet processing (sending).

Client.cpp:
* implement NetworkPacket ::Send interface.
* Move packet handlers to a dedicated file
* Remove Client::Send(SharedBuffer)

Server.cpp:
* implement NetworkPacket ::Send interface.
* Rewrite all packets using NetworkPacket
* Move packet handlers to a dedicated file
* Remove Server::Send(SharedBuffer)

ClientIface.cpp:
* Remove sendToAll(SharedBuffer<u8>)

Connection.hpp rework:
* Remove duplicate include
* Remove duplicate negation
* Remove a useless variable
* Improve code performance by using a m_peers_list instead of scanning m_peers map
* Remove Connection::Send(SharedBuffer)
* Fix useafterfree into NetworkPacket Sending
* Remove unused Connection::sendToAll

Test.cpp:
* Remove dead code
* Update tests to use NetworkPackets

Misc:
* add new wrappers to Send packets in client, using NetworkPacket
* Add NetworkPacket methods for Connection
* coding style fix
* dead code since changes cleanup
* Use v3s16 read instead of reading x,y,z separately in some packets
* Use different files to handle packets received by client and server
* Cleanup: Remove useless includes

ok @Zeno-
Tested by @Zeno- @VanessaE and @nerzhul on running servers

* Increase performance (client)
* Avoid changing a global value to solve a local problem

This reverts commit d25ff8fd.

* Increase performance (client)
* Avoid changing a global value to solve a local problem

* Move networkcode to a dedicated directory
* Rename clientserver.h to network/networkprotocol.h (Better name) and sanitize some includes
* Create object NetworkPacket
  * It stores command (opcode) and data separated
  * It also stores peer_id
  * Data reading can be done by using a streaming interface
* Change packet routing analysis
  * Remove old conditional analysis
  * Now uses function pointed analysis and add connection state ({Client,Server}::handlers)
  * Connection state permit to categorize condition to handle before analyze packets
  * Create a handler for depreciated messages, instead of duplicating code

Disables local map saving for all local server types

See: https://github.com/minetest/minetest/issues/2024

Also add NodeResolver callbacks on the client

NOTE 1: This does not mean a 2x increase in framerate. Increase in fps may be up to 1-2fps
NOTE 2: This local 'caching' of settings is not optimal and an alternative solution will be worked on after 0.4.11 is released

Without this patch node 0,0,0 is highlighted when enable_node_highligting is false
There is a minor lighting issue remaining, however it seems to be related to a different bug (https://github.com/minetest/minetest/issues/1887)

Check if mesh is here before adding to meshcollector.

Fix deleting the meshes.

sky.cpp: m_bgcolor.getAlpha() was being used before initialised

mesh related: m_highlight_mesh_color was being used uninitialised

This also cleans up settings a bit