Bug 182680 Use feature of new Aggregation framework of Data Engine.
DataEngine will implement new aggregation framework in 2.2.0RC0. After the implementation is finished Engine should go ahead to use new column bindings in definition of map/highlight.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ExprManager.java
* @param name
	 * @return
	 * @throws DataException
	 */
	public IBinding getBinding( String name ) throws DataException
	{
		for ( int i = 0; i < bindingExprs.size( ); i++ )
		{
			GroupBindingColumn gcb = (GroupBindingColumn) bindingExprs.get( i );
			if ( entryLevel != OVERALL_GROUP )
			{
				if ( gcb.getGroupLevel( ) > entryLevel )
					continue;
			}
			if( gcb.getBinding( name )!= null )
				return gcb.getBinding( name );
		}
		return null;
	}
	/**
	 * @param name
	 * @return
	 * @throws DataException 
	 */
	private IBaseExpression getBindingExpr( String name ) throws DataException
	{
		for ( int i = 0; i < bindingExprs.size( ); i++ )
		{
			GroupBindingColumn gcb = (GroupBindingColumn) bindingExprs.get( i );
			if ( entryLevel != OVERALL_GROUP )