Bug 143173 No error for recursive including when exporting a report to a library
Steps to reproduce: 1.New a library named "Lib", add a lable in it 2.New a report, extends Lib.label 3.Export the report, choose target library "Lib" Expected result: Error to warn the recursive including Actual result: The target library includes itself without error
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/util/ModelUtil.java
switch ( propDefn.getTypeCode( ) )
		{
			case PropertyType.STRUCT_TYPE :
				if ( propDefn.isList( ) )
					return ModelUtil.cloneStructList( (List) value );
				return ( (Structure) value ).copy( );
			case PropertyType.ELEMENT_REF_TYPE :
			case PropertyType.STRUCT_REF_TYPE :
				ReferenceValue refValue = (ReferenceValue) value;
				return refValue.copy( );
			case PropertyType.LIST_TYPE :
				return ModelUtil.clonePropertyList( (List) value );
		}
		return value;
	}
	/**
	 * Copies a list of simple property values.
	 * 
	 * @param value
	 *            the original value to copy
	 * @return the cloned list of simple property values
	 */
	private static Object clonePropertyList( List value )
	{
		if ( value == null )
			return null;
		ArrayList returnList = new ArrayList( );
		for ( int i = 0; i < value.size( ); i++ )
		{
			Object item = value.get( i );