When holograms are edited/updated, they can duplicate and overlap

[riddle]

This makes our respawn clock almost completely unusable. One of those holograms is live and updates, the other is “dead”.

I presume this is related to #381 – hologram entity stays behind and a new one is created.

Let it also be said that those duplicated holograms never stack beyond two and actually they can revert to correct state after a while. This is probably what you assumed when you displayed

sender.sendMessage("Hologram removed. If it did not disappear, try reconnecting.");

However, I don’t want this to work like that. If you need, please see how it’s done in https://github.com/filoghost/HolographicDisplays