Ready Indicator in the lobby (#1771)

* Ready Indicator in the lobby

* Use SessionID instead of Name

* Don't show ready state when game is already running

* Make Ready List not selectable

* -Remove disconnected sessions from Ready
-Fix showing ReadyStatus when staying in lobby

Content.Shared/SharedGameTicker.cs

@@ -1,7 +1,10 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using Lidgren.Network;
 using Robust.Shared.Interfaces.Network;
+using Robust.Shared.Interfaces.Serialization;
+using Robust.Shared.IoC;
 using Robust.Shared.Network;
 
 namespace Content.Shared
@@ -152,6 +155,57 @@ namespace Content.Shared
             }
         }
 
+        protected class MsgTickerLobbyReady : NetMessage
+        {
+            #region REQUIRED
+
+            public const MsgGroups GROUP = MsgGroups.Command;
+            public const string NAME = nameof(MsgTickerLobbyReady);
+            public MsgTickerLobbyReady(INetChannel channel) : base(NAME, GROUP) { }
+
+            #endregion
+
+            /// <summary>
+            /// The Players Ready (SessionID:ready)
+            /// </summary>
+            public Dictionary<NetSessionId, bool> PlayerReady { get; set; }
+
+            public override void ReadFromBuffer(NetIncomingMessage buffer)
+            {
+                PlayerReady = new Dictionary<NetSessionId, bool>();
+                var length = buffer.ReadInt32();
+                for (int i = 0; i < length; i++)
+                {
+                    var serializer = IoCManager.Resolve<IRobustSerializer>();
+                    var byteLength = buffer.ReadVariableInt32();
+                    NetSessionId sessionID;
+                    using (var stream = buffer.ReadAsStream(byteLength))
+                    {
+                        serializer.DeserializeDirect(stream, out sessionID);
+                    }
+                    var ready = buffer.ReadBoolean();
+                    PlayerReady.Add(sessionID, ready);
+                }
+            }
+
+            public override void WriteToBuffer(NetOutgoingMessage buffer)
+            {
+                var serializer = IoCManager.Resolve<IRobustSerializer>();
+                buffer.Write(PlayerReady.Count);
+                foreach (var p in PlayerReady)
+                {
+                    using (var stream = new MemoryStream())
+                    {
+                        serializer.SerializeDirect(stream, p.Key);
+                        buffer.WriteVariableInt32((int) stream.Length);
+                        stream.TryGetBuffer(out var segment);
+                        buffer.Write(segment);
+                    }
+                    buffer.Write(p.Value);
+                }
+            }
+        }
+
 
         public struct RoundEndPlayerInfo
         {