Bug 129144 Support suppressDuplicates property on table row in report engine
See 129143 for detail. This only needs to be supported for data item in a detail row of a table.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/ir/DataItemDesign.java
{
	/**
	 * Data expression
	 */
	protected Expression value = new Expression( );
	/**
	 * help text
	 */
	protected String helpText;
	/**
	 * help text resource key
	 */
	protected String helpTextKey;
	/**
	 * default constructor. create an empty expression.