Bug 189363 The aggregation of table should be start with sigma symbol
Description: Follow the spec, after specify a aggregation on a table, the aggregation should be represented by starting with the sigma symbol
xtab/org.eclipse.birt.report.item.crosstab.ui/src/org/eclipse/birt/report/item/crosstab/internal/ui/editors/action/AddSubTotalAction.java
count = viewHandle.getLevelCount( );
		for ( int i = 0; i < count; i++ )
		{
			LevelViewHandle tempViewHandle = viewHandle.getLevel( i );
			LevelHandle tempHandle = tempViewHandle.getCubeLevel( );
			List measures = tempViewHandle.getAggregationMeasures( );
			for ( int j = 0; j < measures.size( ); j++ )
			{
				MeasureHandle tempMeasureHandle = ( (MeasureViewHandle) measures.get( j ) ).getCubeMeasure( );
				AggregationDialog.SubTotalInfo info = new AggregationDialog.SubTotalInfo( );
				info.setLevel( tempHandle );
				info.setAggregateOnMeasure( tempMeasureHandle );
				
				info.setFunction(tempMeasureHandle.getFunction( ));
				
				
				
				replaceInfo( info, retValue );
			}
		}
		return retValue;
	}
	private LevelViewHandle getLastLevelViewHandle( )
	{
		DimensionViewHandle viewHandle = getDimensionViewHandle( );
		CrosstabReportItemHandle reportHandle = viewHandle.getCrosstab( );
		int count = reportHandle.getDimensionCount( viewHandle.getAxisType( ) );
		if ( count == 0 )
		{
			return null;