Bug 136241 [regression]Preview template in web viewer and pdf didn't get correct effect.
Description: Preview template items in web viewer and pdf didn't get correct effect. Steps to reproduce: 1. Create template items. 2. Preview in Web Viewer and pdf. Expected result: Same effect as in html. Actual result: In web viewer, see only blank box. In pdf, blank page.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
{
		List clients = new ArrayList( referred.getClientList( ) );
		Iterator iter = clients.iterator( );
		while ( iter.hasNext( ) )
		{
			BackRef ref = (BackRef) iter.next( );
			DesignElement client = ref.element;
			if ( unresolveReference )
			{
				BackRefRecord record = new ElementBackRefRecord( module,
						referred, client, ref.propName );
				getActivityStack( ).execute( record );
			}
			else
			{
				if ( referred.isStyle( ) )
				{
					StyleCommand clientCmd = new StyleCommand( module, client );
					clientCmd.setStyleElement( (DesignElement) null );
				}
				else
				{
					PropertyCommand cmd = new PropertyCommand( module, client );
					cmd.setProperty( ref.propName, null );
				}
			}
		}
	}
	/**
	 * Clears references of elements that are referred by the to-be-deleted