Modernize project codebase (#906)

* 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

* Add safety checks and fix a issue with vector going OOR

Minecraft.World/WeighedRandom.cpp

@@ -28,7 +28,7 @@ WeighedRandomItem *WeighedRandom::getRandomItem(Random *random, vector<WeighedRa
             return item;
         }
 	}
-    return NULL;
+    return nullptr;
 }
 
 WeighedRandomItem *WeighedRandom::getRandomItem(Random *random, vector<WeighedRandomItem *> *items)
@@ -62,7 +62,7 @@ WeighedRandomItem *WeighedRandom::getRandomItem(Random *random, WeighedRandomIte
             return items[i];
         }
 	}
-    return NULL;
+    return nullptr;
 }