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.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/GetParameterDefinitionTask.java
* groups to the <code>allParameters</code> object.
	 * 
	 * @param params
	 *            A collection of parameters and parameter groups.
	 */
	protected ArrayList flattenParameter( ArrayList params )
	{
		assert params != null;
		IParameterDefnBase param;
		ArrayList allParameters = new ArrayList( );
		for ( int n = 0; n < params.size( ); n++ )
		{
			param = (IParameterDefnBase) params.get( n );
			if ( param.getParameterType( ) == IParameterDefnBase.PARAMETER_GROUP
					|| param.getParameterType( ) == IParameterDefnBase.CASCADING_PARAMETER_GROUP )
			{
				allParameters
						.addAll( flattenParameter( ( (IParameterGroupDefn) param )
								.getContents( ) ) );
			}
			else
			{
				allParameters.add( param );
			}
		}
		
		return allParameters;
	}
	
	class ParameterIRVisitor extends DesignVisitor