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/MycelTile.cpp

@@ -6,8 +6,8 @@
 
 MycelTile::MycelTile(int id) : Tile(id, Material::grass)
 {
-	iconTop = NULL;
-	iconSnowSide = NULL;
+	iconTop = nullptr;
+	iconSnowSide = nullptr;
 	setTicking(true);
 }