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/MushroomIslandBiome.cpp

@@ -13,7 +13,7 @@ MushroomIslandBiome::MushroomIslandBiome(int id) : Biome(id)
     decorator->mushroomCount = 1;
     decorator->hugeMushrooms = 1;
 
-    topMaterial = (byte) Tile::mycel_Id;
+    topMaterial = static_cast<byte>(Tile::mycel_Id);
 
     enemies.clear();
     friendlies.clear();