Add missing signals in history model

{begin|end}InsertRows were not emitted

src/historymodel.cpp

@@ -268,12 +268,12 @@ HistoryTopLevelItem* HistoryModelPrivate::getCategory(const Call* call)
       category = new HistoryTopLevelItem(name,index);
       category->modelRow = m_lCategoryCounter.size();
       //emit layoutAboutToBeChanged(); //Not necessary
-//       beginInsertRows(QModelIndex(),m_lCategoryCounter.size(),m_lCategoryCounter.size());
+      HistoryModel::instance()->beginInsertRows(QModelIndex(),m_lCategoryCounter.size(),m_lCategoryCounter.size());
       category->m_AbsoluteIndex = m_lCategoryCounter.size();
       m_lCategoryCounter << category;
       m_hCategories    [index] = category;
       m_hCategoryByName[name ] = category;
-//       endInsertRows();
+      HistoryModel::instance()->endInsertRows();
       //emit layoutChanged();
    }
    return category;