Split chat lines into pools

- Add a common class for passing around chat lines
- Add wrapper methods for adding chat lines
- Combine repeated chat lines in the display widget

OpenRA.Game/Settings.cs

@@ -33,6 +33,12 @@ namespace OpenRA
 		Incompatible = 16
 	}
 
+	[Flags]
+	public enum TextNotificationPoolFilters
+	{
+		None = 0
+	}
+
 	public enum WorldViewport { Native, Close, Medium, Far }
 
 	public class ServerSettings
@@ -265,6 +271,8 @@ namespace OpenRA
 
 		[Desc("Allow mods to enable the Discord service that can interact with a local Discord client.")]
 		public bool EnableDiscordService = true;
+
+		public TextNotificationPoolFilters TextNotificationPoolFilters = TextNotificationPoolFilters.None;
 	}
 
 	public class Settings