Fix TraceManager.currentFrameSize

BauSystem_Main/src/de/steamwar/bausystem/tracer/TraceManager.java

@@ -60,6 +60,7 @@ public class TraceManager {
     }
 
     public static int currentFrameSize() {
+        if (!frameMap.containsKey(currentFrame)) return 0;
         return frameMap.get(currentFrame).size();
     }