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 tag
	 *            the tag to write
	 * @param name
	 *            the property name or member name
	 * @param value
	 *            the xml value
	 * @param cdata
	 *            whether the values should be written as CDATA.
	 */
	protected void writeEntry( String tag, String name, String value,
			boolean cdata )
	{
		writer.startElement( tag );
		if ( name != null )
			writer.attribute( DesignSchemaConstants.NAME_ATTRIB, name );
		if ( cdata )
			writer.textCDATA( value );
		else
			writer.text( value );
		writer.endElement( );
	}
	/**
	 * Writes a list of extended property structure.
	 * 
	 * @param properties
	 *            the list of Extended property structure to write.
	 * @param propName
	 *            the tag name for Extended property list.
	 */