Refactor GameSpeed setting

*Remove internal GameSpeed defaults
 Enforce setting values explicitly all the time
 Require definition of a DefaultSpeed

*Remove Global.Timestep default

*Remove the hacky Timestep/OrderLatency setting via LobbyInfo

*Fix shellmaps ignoring mod-defined gamespeeds

*Make DateTimeGlobal use the MapOptions gamespeed

OpenRA.Game/Network/ReplayConnection.cs

@@ -27,7 +27,10 @@ namespace OpenRA.Network
 
 		Queue<Chunk> chunks = new Queue<Chunk>();
 		List<byte[]> sync = new List<byte[]>();
+
+		readonly int orderLatency;
 		int ordersFrame;
+
 		Dictionary<int, int> lastClientsFrame = new Dictionary<int, int>();
 
 		public int LocalClientId => -1;
@@ -122,7 +125,10 @@ namespace OpenRA.Network
 				}
 			}
 
-			ordersFrame = LobbyInfo.GlobalSettings.OrderLatency;
+			var gameSpeeds = Game.ModData.Manifest.Get<GameSpeeds>();
+			var gameSpeedName = LobbyInfo.GlobalSettings.OptionOrDefault("gamespeed", gameSpeeds.DefaultSpeed);
+			orderLatency = gameSpeeds.Speeds[gameSpeedName].OrderLatency;
+			ordersFrame = orderLatency;
 		}
 
 		// Do nothing: ignore locally generated orders
@@ -137,7 +143,7 @@ namespace OpenRA.Network
 			sync.Add(ms.GetBuffer());
 
 			// Store the current frame so Receive() can return the next chunk of orders.
-			ordersFrame = frame + LobbyInfo.GlobalSettings.OrderLatency;
+			ordersFrame = frame + orderLatency;
 		}
 
 		public void Receive(Action<int, byte[]> packetFn)

OpenRA.Game/Network/Session.cs

@@ -222,8 +222,6 @@ namespace OpenRA.Network
 		{
 			public string ServerName;
 			public string Map;
-			public int Timestep = 40;
-			public int OrderLatency = 3; // net tick frames (x 120 = ms)
 			public int RandomSeed = 0;
 			public bool AllowSpectators = true;
 			public string GameUid;

OpenRA.Game/Network/UnitOrders.cs

@@ -254,7 +254,6 @@ namespace OpenRA.Network
 				case "SyncInfo":
 					{
 						orderManager.LobbyInfo = Session.Deserialize(order.TargetString);
-						SetOrderLag(orderManager);
 						Game.SyncLobbyInfo();
 						break;
 					}
@@ -304,7 +303,6 @@ namespace OpenRA.Network
 								orderManager.LobbyInfo.GlobalSettings = Session.Global.Deserialize(node.Value);
 						}
 
-						SetOrderLag(orderManager);
 						Game.SyncLobbyInfo();
 						break;
 					}
@@ -354,14 +352,5 @@ namespace OpenRA.Network
 			if (world.OrderValidators.All(vo => vo.OrderValidation(orderManager, world, clientId, order)))
 				order.Subject.ResolveOrder(order);
 		}
-
-		static void SetOrderLag(OrderManager o)
-		{
-			if (o.FramesAhead != o.LobbyInfo.GlobalSettings.OrderLatency && !o.GameStarted)
-			{
-				o.FramesAhead = o.LobbyInfo.GlobalSettings.OrderLatency;
-				Log.Write("server", "Order lag is now {0} frames.", o.LobbyInfo.GlobalSettings.OrderLatency);
-			}
-		}
 	}
 }