Bug 179737 The MeasureHandle should be able to provide data type info
We are now allow user input expression as measure expression. However this brings difficulties in determine the data type of a measure expression evaluation result. We need MeasureHandle to be enhanced to include the data type info. Please note that data type "any" is not accepted.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
propertyCDATA( obj, IOdaDataSetModel.DESIGNER_VALUES_PROP );
		List properties = (List) obj.getLocalProperty( getModule( ),
				IOdaDataSetModel.PRIVATE_DRIVER_PROPERTIES_PROP );
		writeExtendedProperties( properties,
				IOdaDataSetModel.PRIVATE_DRIVER_PROPERTIES_PROP );
		writeOdaExtensionProperties( obj,
				IOdaExtendableElementModel.EXTENSION_ID_PROP );
		writer.endElement( );
	}
	/**
	 * Writes the columns slot of <code>GridItem</code> and
	 * <code>TableItem</code>.
	 * 
	 * @param obj
	 *            the grid item or table item
	 * @param slot
	 *            the columns slot
	 */
	private void writeColumns( DesignElement obj, int slot )
	{
		assert obj instanceof GridItem || obj instanceof TableItem;
		assert slot == IGridItemModel.COLUMN_SLOT
				|| slot == ITableItemModel.COLUMN_SLOT;
		
		
		
		boolean revert = true;
		if ( revert )
		{
			writeContents( obj, slot, null );