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
* @param memberName
	 *            the member name
	 * @param cdata
	 *            whether the value should be written as CDATA
	 * @param withoutName
	 *            whether the property name should be written
	 */
	protected void writeProperty( IStructure struct, String tag,
			String memberName, boolean cdata, boolean withoutName )
	{
		StructureDefn structDefn = (StructureDefn) struct.getDefn( );
		assert structDefn != null;
		StructPropertyDefn propDefn = (StructPropertyDefn) structDefn
				.getMember( memberName );
		assert propDefn != null;
		Object value = null;
		if ( struct instanceof Structure )
			value = ( (Structure) struct ).getLocalProperty( getModule( ),
					propDefn );
		else
		{
			assert struct instanceof UserPropertyDefn;
			value = ( (UserPropertyDefn) struct ).getLocalProperty(
					getModule( ), propDefn );
		}
		if ( value == null )
			return;
		String xml = propDefn.getXmlValue( getModule( ), value );
		if ( xml == null )
			return;