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 obj
	 *            the design element
	 * @param propName
	 *            the property name
	 */
	protected void property( DesignElement obj, String propName )
	{
		writeProperty( obj, null, propName, false );
	}
	/**
	 * Writes one property entry of an structure.
	 * 
	 * @param structure
	 *            the structure
	 * @param memberName
	 *            the member name
	 */
	protected void property( IStructure structure, String memberName )
	{
		writeProperty( structure, null, memberName, false, false );
	}
	/**
	 * Writes one property entry of an element as CDATA.
	 * 
	 * @param obj
	 *            the design element
	 * @param propName
	 *            the property name
	 */
	protected void propertyCDATA( DesignElement obj, String propName )