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
writer.attribute( DesignSchemaConstants.NAME_ATTRIB, propName );
		IStructureDefn structDefn = prop.getStructDefn( );
		Iterator iter = structDefn.propertiesIterator( );
		while ( iter.hasNext( ) )
		{
			StructPropertyDefn strcutPropDefn = (StructPropertyDefn) iter
					.next( );
			
			
			writeMember( struct, strcutPropDefn );
		}
		writer.endElement( );
	}
	/**
	 * Write property or structure according to definition.
	 * 
	 * @param struct
	 *            parent structure.
	 * @param propDefn
	 *            property definition.
	 */
	private void writeMember( IStructure struct, PropertyDefn propDefn )
	{
		
		
		String propName = propDefn.getName( );
		switch ( propDefn.getTypeCode( ) )
		{
			case IPropertyType.STRUCT_TYPE :
				if ( propDefn.isList( ) )