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.tests/test/org/eclipse/birt/report/model/parser/TabularCubeParserTest.java
import org.eclipse.birt.report.model.api.core.IDesignElement;
import org.eclipse.birt.report.model.api.core.Listener;
import org.eclipse.birt.report.model.api.elements.DesignChoiceConstants;
import org.eclipse.birt.report.model.api.elements.structures.DimensionCondition;
import org.eclipse.birt.report.model.api.elements.structures.DimensionJoinCondition;
import org.eclipse.birt.report.model.api.elements.structures.LevelAttribute;
import org.eclipse.birt.report.model.api.elements.structures.Rule;
import org.eclipse.birt.report.model.api.olap.DimensionHandle;
import org.eclipse.birt.report.model.api.olap.HierarchyHandle;
import org.eclipse.birt.report.model.api.olap.LevelHandle;
import org.eclipse.birt.report.model.api.olap.MeasureGroupHandle;
import org.eclipse.birt.report.model.api.olap.MeasureHandle;
import org.eclipse.birt.report.model.api.olap.TabularCubeHandle;
import org.eclipse.birt.report.model.api.olap.TabularHierarchyHandle;
import org.eclipse.birt.report.model.api.olap.TabularLevelHandle;
import org.eclipse.birt.report.model.elements.interfaces.IAccessControlModel;
import org.eclipse.birt.report.model.elements.interfaces.ICubeModel;
import org.eclipse.birt.report.model.elements.interfaces.ILevelModel;
import org.eclipse.birt.report.model.elements.interfaces.IReportDesignModel;
import org.eclipse.birt.report.model.elements.interfaces.IValueAccessControlModel;
import org.eclipse.birt.report.model.util.BaseTestCase;
/**
 * Tests the cube element.
 */
public class TabularCubeParserTest extends BaseTestCase
{
	private final String FILE_NAME = "CubeParserTest.xml"; 
	private final String FILE_NAME_EXTENDS = "CubeParserTest_3.xml"; 
	/**
	 *