Added comand for trace at

BauSystem_Main/src/de/steamwar/bausystem/features/tracer/TraceCommand.java

@@ -91,10 +91,18 @@ public class TraceCommand extends SWCommand {
     }
 
     @Register(value = "isolate", description = "TRACE_COMMAND_HELP_SHOW")
-    public void isolate(Player player, Trace trace,  @ErrorMessage("test") TNTRecord... records){
+    public void isolate(Player player, Trace trace,  @ErrorMessage("TRACE_RECORD_ID_INVALID") TNTRecord... records){
         trace.isolate(player, records);
     }
-    //TODO warning if nothing is shown
+
+    @Register(value="at", description = "TRACE_COMMAND_HELP_SHOW")
+    public void at(Player player, int start, int end){
+        for(Trace trace: manager.getAll()){
+            trace.renderAt(player, start, end);
+        }
+    }
+
+
 
     @ClassMapper(value = Trace.class, local = true)
     public TypeMapper<Trace> traceClassMapper(){