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/SnowballItem.cpp

@@ -18,6 +18,6 @@ shared_ptr<ItemInstance> SnowballItem::use(shared_ptr<ItemInstance> instance, Le
 		instance->count--;
 	}
 	level->playEntitySound((shared_ptr<Entity> ) player, eSoundType_RANDOM_BOW, 0.5f, 0.4f / (random->nextFloat() * 0.4f + 0.8f));
-	if (!level->isClientSide) level->addEntity( shared_ptr<Snowball>( new Snowball(level, player) ) );
+	if (!level->isClientSide) level->addEntity(std::make_shared<Snowball>(level, player));
 	return instance;
 }