Fixed duplicate console and player messages when built in server commands where used or an unknown command was issued

src/main/java/org/bukkit/craftbukkit/command/ServerCommandListener.java

@@ -0,0 +1,36 @@
+package org.bukkit.craftbukkit.command;
+
+import java.lang.reflect.Method;
+
+import net.minecraft.server.ICommandListener;
+
+import org.bukkit.command.CommandSender;
+
+public class ServerCommandListener implements ICommandListener {
+    private final CommandSender commandSender;
+    private final String prefix;
+
+    public ServerCommandListener(CommandSender commandSender) {
+        this.commandSender = commandSender;
+        String[] parts = commandSender.getClass().getName().split("\\.");
+        this.prefix = parts[parts.length-1];
+    }
+
+    public void sendMessage(String msg) {
+        this.commandSender.sendMessage(msg);
+    }
+
+    public CommandSender getSender() {
+        return commandSender;
+    }
+
+    public String getName() {
+        try {
+            Method getName = commandSender.getClass().getMethod( "getName" );
+            return (String) getName.invoke(commandSender);
+        } catch (Exception e) {
+        }
+
+        return this.prefix;
+    }
+}