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/DetectorRailTile.cpp

@@ -12,7 +12,7 @@
 DetectorRailTile::DetectorRailTile(int id) : BaseRailTile(id, true)
 {
 	setTicking(true);
-	icons = NULL;
+	icons = nullptr;
 }
 
 int DetectorRailTile::getTickDelay(Level *level)