Removed Threading in ExecutionTimeSubject because of JavaFX Thread problem

src/main/java/fabrik/simulator/pic16f84/Timer.java

@@ -67,6 +67,7 @@ public class Timer extends PICComponent implements TimerInterface, ExecutionTime
     @Override
     public void initialize(PICComponentLocator locator) {
         super.initialize(locator);
+        executionTime.registerObserver(this);
     }
 
     @Override