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/MinecartTNT.cpp

@@ -66,7 +66,7 @@ void MinecartTNT::destroy(DamageSource *source)
 
 	if (!source->isExplosion())
 	{
-		spawnAtLocation( shared_ptr<ItemInstance>( new ItemInstance(Tile::tnt, 1) ), 0);
+		spawnAtLocation(std::make_shared<ItemInstance>(Tile::tnt, 1), 0);
 	}
 
 	if (source->isFire() || source->isExplosion() || speedSqr >= 0.01f)
@@ -81,7 +81,7 @@ void MinecartTNT::explode(double speedSqr)
 	{
 		double speed = sqrt(speedSqr);
 		if (speed > 5) speed = 5;
-		level->explode(shared_from_this(), x, y, z, (float) (4 + random->nextDouble() * 1.5f * speed), true);
+		level->explode(shared_from_this(), x, y, z, static_cast<float>(4 + random->nextDouble() * 1.5f * speed), true);
 		remove();
 	}
 }