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
property( obj, IScalarParameterModel.CONTROL_TYPE_PROP );
		property( obj, IScalarParameterModel.ALIGNMENT_PROP );
		property( obj, IScalarParameterModel.DATASET_NAME_PROP );
		property( obj, IScalarParameterModel.VALUE_EXPR_PROP );
		property( obj, IScalarParameterModel.LABEL_EXPR_PROP );
		property( obj, IScalarParameterModel.MUCH_MATCH_PROP );
		property( obj, IScalarParameterModel.FIXED_ORDER_PROP );
		property( obj, IScalarParameterModel.DEFAULT_VALUE_PROP );
		property( obj, IScalarParameterModel.DISTINCT_PROP );
		property( obj, IScalarParameterModel.SORT_BY_PROP );
		property( obj, IScalarParameterModel.SORT_DIRECTION_PROP );
		writeStructure( obj, IScalarParameterModel.FORMAT_PROP );
		writeStructureList( obj, IScalarParameterModel.SELECTION_LIST_PROP );
		writeStructureList( obj, IReportItemModel.BOUND_DATA_COLUMNS_PROP );
		writer.endElement( );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.elements.ElementVisitor#visitTemplateDataSet(org.eclipse.birt.report.model.elements.TemplateDataSet)
	 */
	public void visitTemplateDataSet( TemplateDataSet obj )
	{
		writer.startElement( DesignSchemaConstants.TEMPLATE_DATA_SET_TAG );
		super.visitTemplateDataSet( obj );
		writer.endElement( );
	}
	/*
	 * (non-Javadoc)
	 *