Bug 213126 Add support for DataEngine-leve dataset cache
In many cases the DataEngine-leve dataset cache is useful which ensure that a dataset is executed one time during rendering one report. To support this feature a new dataset property should be added. The Birt customer can choose whether this dataset need to be cached or not by setting the property in deisgn time.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
*            whether the values should be written as CDATA.
	 */
	protected void writeEntry( String tag, String name, String encryptionID,
			String value, boolean cdata )
	{
		writer.startElement( tag );
		if ( name != null )
			writer.attribute( DesignSchemaConstants.NAME_ATTRIB, name );
		if ( encryptionID != null )
			writer.attribute( DesignSchemaConstants.ENCRYPTION_ID_ATTRIB,
					encryptionID );
		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.
	 */
	protected void writeExtendedProperties( List properties, String propName )
	{
		if ( properties != null && properties.size( ) != 0 )
		{
			writer.startElement( DesignSchemaConstants.LIST_PROPERTY_TAG );