Add MapClassification.Generated.

Generated maps are created at runtime using a
mod-defined trait. They are embedded directly
into replays and save games as they exist in
memory only, and disappear after the game exits.

OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs

@@ -667,6 +667,21 @@ namespace OpenRA.Mods.Common.Server
 				var m = server.ModData.MapCache[s];
 				if (m.Status == MapStatus.Available || m.Status == MapStatus.DownloadAvailable)
 					SelectMap(m);
+				else if (m.Class == MapClassification.Generated)
+				{
+					if (m.Status == MapStatus.Generating)
+					{
+						// Wait up to 5 seconds for the map to be generated
+						var stopwatch = Stopwatch.StartNew();
+						while (m.Status == MapStatus.Generating && stopwatch.ElapsedMilliseconds < 5000)
+							Thread.Sleep(100);
+					}
+
+					if (m.Status == MapStatus.Available)
+						SelectMap(m);
+					else
+						QueryFailed();
+				}
 				else if (server.Settings.QueryMapRepository)
 				{
 					server.SendFluentMessageTo(conn, SearchingMap);