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/SignItem.cpp

@@ -49,7 +49,7 @@ bool SignItem::useOn(shared_ptr<ItemInstance> instance, shared_ptr<Player> playe
 
 		instance->count--;
 		shared_ptr<SignTileEntity> ste = dynamic_pointer_cast<SignTileEntity>( level->getTileEntity(x, y, z) );
-		if (ste != NULL) player->openTextEdit(ste);
+		if (ste != nullptr) player->openTextEdit(ste);
 
 		// 4J-JEV: Hook for durango 'BlockPlaced' event.
 		player->awardStat(