This should improve compilation speed.
Things changed:
* Prefer forward-declarations in headers.
* Move header-includes out of headers if possible.
* Move some functions definitions out of headers.
* Put some member variables into unique_ptrs (see Client).
* 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
* Rename IWritableNodeDefManager to NodeDefManager
* Make INodeDefManager functions const
* Use "const *NodeDefManager" instead of "*INodeDefManager"
* Remove unused INodeDefManager class
* Merge NodeDefManager and CNodeDefManager
* Document NodeDefManager
* squashed: CSM: Implement register_globalstep
* Re-use fatal error mechanism from server to disconnect client on CSM error
* Little client functions cleanups
* squashed: CSM: add core.after function
* core.after is shared code between client & server
* ModApiUtil get_us_time feature enabled for client
* rename GameScripting to ServerScripting
* Make getBuiltinLuaPath static serverside
* Add on_shutdown callback
* Add on_receiving_chat_message & on_sending_chat_message callbacks
* ScriptApiBase: use IGameDef instead of Server
This permits to share common attribute between client & server
* Enable mod security in client side modding without conditions
