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/TileEntityDataPacket.cpp

@@ -10,7 +10,7 @@ void TileEntityDataPacket::_init()
 {
 	x = y = z = 0;
 	type = TYPE_MOB_SPAWNER;
-	tag = NULL;
+	tag = nullptr;
 }
 
 
@@ -50,7 +50,7 @@ void TileEntityDataPacket::write(DataOutputStream *dos)
 	dos->writeInt(x);
 	dos->writeShort(y);
 	dos->writeInt(z);
-	dos->writeByte((byte) type);
+	dos->writeByte(static_cast<byte>(type));
 	writeNbt(tag, dos);
 }