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
switch ( prop.getTypeCode( ) )
				{
					case IPropertyType.LIST_TYPE :
						writeSimplePropertyList( obj, propName );
						break;
					case IPropertyType.XML_TYPE :
						if ( obj.hasLocalPropertyValuesOnOwnModel( ) )
							writeProperty( obj, ModelUtil
									.getTagByPropertyType( prop ), propName,
									true );
						break;
					case IPropertyType.STRUCT_TYPE :
						if ( prop.isList( ) )
							writeStructureList( obj, propName );
						else
							writeStructure( obj, propName );
						break;
					case IPropertyType.ELEMENT_TYPE :
					case IPropertyType.CONTENT_ELEMENT_TYPE :
						writeContents( obj, propName );
						break;
					default :
						writeProperty( obj, ModelUtil
								.getTagByPropertyType( prop ), prop.getName( ),
								false );
						break;
				}