Bug 209128 BIRT Cross tab Model Change - Support for filter on measures
TO support filter condition on cross tab measure, Model changes are needed to support filter condition list on cross tab report item.
xtab/org.eclipse.birt.report.item.crosstab.core/src/org/eclipse/birt/report/item/crosstab/core/de/MeasureViewHandle.java
* 
	 * @param dimensionName
	 *            name of the dimension to find
	 * @param levelName
	 *            name of the level to find
	 * @return the header cell which refers the given dimension and level
	 */
	public CrosstabCellHandle getHeader( )
	{
		DesignElementHandle headerCell = getHeaderCell( );
		return (CrosstabCellHandle) ( headerCell == null ? null : CrosstabUtil
				.getReportItem( headerCell, CROSSTAB_CELL_EXTENSION_NAME ) );
	}
	/**
	 * Gets measure header cell.
	 * 
	 * @return the design element handle for the header cell if found, otherwise
	 *         null
	 */
	private DesignElementHandle getHeaderCell( )
	{
		PropertyHandle propHandle = getHeaderProperty( );
		if ( propHandle.getContentCount( ) <= 0 )
			return null;
		return propHandle.getContent( 0 );
	}
	/**
	 * Removes header cell for current measure.
	 * 
	 * @throws SemanticException