Bug 211703 Support muti-view on report item.
As title described.
xtab/org.eclipse.birt.report.item.crosstab.core/src/org/eclipse/birt/report/item/crosstab/core/de/internal/CrosstabReportItemTask.java
{
			MeasureViewHandle measureView = crosstab.getMeasure( i );
			if ( measures.contains( measureView ) )
				continue;
			if ( CrosstabModelUtil
					.isAggregationOn( measureView, null, axisType ) )
				measures.add( measureView );
		}
		return measures;
	}
	/**
	 * Gets the aggregation function for the row/column grand total in the
	 * crosstab.
	 * 
	 * @param crosstab
	 * @param axisType
	 * @param measureView
	 * @return
	 */
	public String getAggregationFunction( int axisType,
			MeasureViewHandle measureView )
	{
		
		if ( crosstab == null || crosstab.getGrandTotal( axisType ) == null
				|| measureView == null || crosstab != measureView.getCrosstab( ) )
			return null;
		for ( int j = 0; j < measureView.getAggregationCount( ); j++ )
		{
			AggregationCellHandle cell = measureView.getAggregationCell( j );
			if ( ( axisType == COLUMN_AXIS_TYPE && cell