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/Enemy.cpp

@@ -5,5 +5,5 @@ EntitySelector *Enemy::ENEMY_SELECTOR = new Enemy::EnemyEntitySelector();
 
 bool Enemy::EnemyEntitySelector::matches(shared_ptr<Entity> entity) const
 {
-	return (entity != NULL) && entity->instanceof(eTYPE_ENEMY);
+	return (entity != nullptr) && entity->instanceof(eTYPE_ENEMY);
 }