Bug 188578 Add "displayColumnName" on TabularLevel
Add Property "displayColumnName" on TabbularLevel and corresponding APIs on handle. Property Type: expression.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
|| IDesignElementModel.EXTENDS_PROP.equals( propName ) )
					continue;
				
				
				
				
				
				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