Bug 182895 Support sort on Level attribute.
Currently in OLAP engine we only support sort on level key value. We should go ahead to support sort on level attribute value.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/olap/driver/DimensionAxis.java
public boolean first( ) throws OLAPException
	{
		return this.edgeInfo.dim_first( dimAxisIndex );
	}
	/**
	 * Moves cursor to last row. Returns false if the result set is empty
	 * 
	 * @return
	 * @throws OLAPException
	 */
	public boolean last( ) throws OLAPException
	{
		return this.edgeInfo.dim_last( dimAxisIndex );
	}
	/**
	 * 
	 * @return
	 */
	public boolean isBeforeFirst( )
	{
		return this.edgeInfo.dim_isBeforeFirst( dimAxisIndex );
	}
	/**
	 * 
	 * @return
	 * @throws OLAPException
	 */
	public boolean isAfterLast( ) throws OLAPException
	{
		return this.edgeInfo.dim_isAfterLast( dimAxisIndex );