removing children when report is updated

* otherwise items will always be appended

Author: Death111

src/main/java/de/doubleslash/keeptime/view/ReportController.java

@@ -193,7 +193,7 @@ protected void updateItem(final TableRow item, final boolean empty) {
 
    private void updateReport(final LocalDate dateToShow) {
       this.currentReportDate = dateToShow;
-
+      rootItem.getChildren().clear();
       reportRoot.requestFocus();
 
       this.currentDayLabel.setText(DateFormatter.toDayDateString(this.currentReportDate));