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/SmallFireball.cpp

@@ -25,7 +25,7 @@ void SmallFireball::onHit(HitResult *res)
 {
 	if (!level->isClientSide)
 	{
-		if (res->entity != NULL)
+		if (res->entity != nullptr)
 		{
 			DamageSource *damageSource = DamageSource::fireball(dynamic_pointer_cast<Fireball>(shared_from_this()),owner);
 			if (!res->entity->isFireImmune() && res->entity->hurt(damageSource, 5))