remove unneccessary dependencies, make SendTo less spammy

OpenRA.Game/Server/Server.cs

@@ -13,13 +13,11 @@ using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Text;
 using System.Net;
 using System.Net.Sockets;
 using System.Net.NetworkInformation;
 using UPnP;
 using System.Threading;
-using System.Xml;
 using OpenRA.FileFormats;
 using OpenRA.GameRules;
 using OpenRA.Network;