Hologram class based on invisible players.

Hologram.cs

	public class Hologram : Mob
	{
		public UUID Uuid { get; private set; }
		public string Name { get; private set; }
		public bool Silent { get; set; }
		public bool HideNameTag { get; set; }
		public bool NoAi { get; set; }

		public Hologram(Level level) : base(63, level)
		{
			Uuid = new UUID(Guid.NewGuid().ToByteArray());

			Width = 0.6;
			Length = 0.6;
			Height = 1.80;

			IsSpawned = false;

			IsInvisible = true;

			HealthManager = new ActionHealthManager(this, (source) =>
			{
			});

		}

		[Wired]
		public void SetNameTag(string nameTag)
		{
			NameTag = nameTag;

			BroadcastSetEntityData();
		}

		public override MetadataDictionary GetMetadata()
		{
			MetadataDictionary metadata = base.GetMetadata();
			metadata[0] = new MetadataByte(GetDataValue());
			metadata[1] = new MetadataShort(HealthManager.Air);
			metadata[2] = new MetadataString(NameTag ?? Name);
			metadata[3] = new MetadataByte(!HideNameTag);
			metadata[4] = new MetadataByte(Silent);
			metadata[7] = new MetadataInt(0); // Potion Color
			metadata[8] = new MetadataByte(0); // Potion Ambient
			metadata[15] = new MetadataByte(NoAi);
			metadata[16] = new MetadataByte(0); // Player flags
			metadata[23] = new MetadataInt(-1); // Leads EID (target or holder?)
			metadata[24] = new MetadataByte(0); // Leads on/off

			return metadata;
		}

		public override void SpawnToPlayers(Player[] players)
		{
			{
				McpeAddPlayer message = McpeAddPlayer.CreateObject();
				message.uuid = Uuid;
				message.username = NameTag ?? Name;
				message.entityId = EntityId;
				message.x = KnownPosition.X;
				message.y = (float) (KnownPosition.Y - Height);
				message.z = KnownPosition.Z;
				message.yaw = KnownPosition.Yaw;
				message.headYaw = KnownPosition.HeadYaw;
				message.pitch = KnownPosition.Pitch;
				message.metadata = GetMetadata();
				Level.RelayBroadcast(players, message);
			}
		}

		public override void DespawnFromPlayers(Player[] players)
		{
			McpeRemoveEntity mcpeRemovePlayer = McpeRemoveEntity.CreateObject();
			mcpeRemovePlayer.entityId = EntityId;
			Level.RelayBroadcast(players, mcpeRemovePlayer);
		}
	}