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/LeverTile.cpp

@@ -10,7 +10,7 @@ LeverTile::LeverTile(int id) : Tile(id, Material::decoration,isSolidRender())
 
 AABB *LeverTile::getAABB(Level *level, int x, int y, int z)
 {
-	return NULL;
+	return nullptr;
 }
 
 bool LeverTile::blocksLight()