Project modernization (#630)

* Fixed boats falling and a TP glitch #266

* Replaced every C-style cast with C++ ones

* Replaced every C-style cast with C++ ones

* Fixed boats falling and a TP glitch #266

* Updated NULL to nullptr and fixing some type issues

* Modernized and fixed a few bugs

- Replaced most instances of `NULL` with `nullptr`.
- Replaced most `shared_ptr(new ...)` with `make_shared`.
- Removed the `nullptr` macro as it was interfering with the actual nullptr keyword in some instances.

* Fixing more conflicts

* Replace int loops with size_t and start work on overrides

Minecraft.World/LevelSettings.cpp

@@ -3,10 +3,10 @@
 #include "net.minecraft.world.level.storage.h"
 #include "LevelType.h"
 
-GameType *GameType::NOT_SET = NULL;
-GameType *GameType::SURVIVAL= NULL;
-GameType *GameType::CREATIVE = NULL;
-GameType *GameType::ADVENTURE = NULL;
+GameType *GameType::NOT_SET = nullptr;
+GameType *GameType::SURVIVAL= nullptr;
+GameType *GameType::CREATIVE = nullptr;
+GameType *GameType::ADVENTURE = nullptr;
 
 void GameType::staticCtor()
 {