fix: add splitscreen, fix dlcs not loading, major RCE vuln fix on packet net, fix chunk loading on non-server clients, persistent saves

note: I changed how XUID works, player data might be wiped on old saves, save items on a chest or similar before trying to load old saves on new version

Minecraft.World/ContainerSetSlotPacket.cpp

@@ -35,7 +35,7 @@ void ContainerSetSlotPacket::read(DataInputStream *dis) //throws IOException
 	// 4J Stu - TU-1 hotfix
 	// Fix for #13142 - Holding down the A button on the furnace ingredient slot causes the UI to display incorrect item counts
 	BYTE byteId = dis->readByte();
-	containerId = *(char *)&byteId;
+	containerId = (char)(signed char)byteId;
 	slot = dis->readShort();
 	item = readItem(dis);
 }