Make bots first-class players.

- Bots have their own Clients, with unique ClientIDs
 - Hosts can set bot team/color in the lobby
 - Bots are kicked when switching to a smaller map without enough slots
 - Order validator assumes that only client 0 has permission to issue bot orders

OpenRA.Mods.Cnc/Widgets/Logic/CncReplayBrowserLogic.cs

@@ -78,7 +78,8 @@ namespace OpenRA.Mods.Cnc.Widgets.Logic
 				panel.GetWidget<LabelWidget>("MAP_TITLE").GetText =
 					() => currentMap != null ? currentMap.Title : "(Unknown Map)";
 
-				var players = currentSummary.LobbyInfo.Slots.Count(s => currentSummary.LobbyInfo.ClientInSlot(s.Key) != null || s.Value.Bot != null);
+				var players = currentSummary.LobbyInfo.Slots
+					.Count(s => currentSummary.LobbyInfo.ClientInSlot(s.Key) != null);
 				panel.GetWidget<LabelWidget>("PLAYERS").GetText = () => players.ToString();
 			}
 			catch (Exception e)