Bug 212497 Need api to get all referencable report item with cube
Need model provide new api to return all referencable report items for dataset or cube respectively. For instance: getAvailableDataSetBindingReferenceList(); getAvailableCubeBindingReferenceList(); also keep current api: getAvailableDataBindingReferenceList().
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ReportItemHandle.java
* @return toc handle
	 */
	public TOCHandle getTOC( )
	{
		PropertyHandle propHandle = getPropertyHandle( IReportItemModel.TOC_PROP );
		if ( propHandle == null )
			return null;
		TOC toc = (TOC) propHandle.getValue( );
		if ( toc == null )
			return null;
		return (TOCHandle) toc.getHandle( propHandle );
	}
	/**
	 * Adds toc structure.
	 * 
	 * @param expression
	 *            toc expression
	 * @return toc handle
	 * @throws SemanticException
	 */
	public TOCHandle addTOC( String expression ) throws SemanticException
	{
		if ( StringUtil.isEmpty( expression ) )
			return null;
		TOC toc = StructureFactory.createTOC( expression );
		setProperty( IReportItemModel.TOC_PROP, toc );
		return (TOCHandle) toc
				.getHandle( getPropertyHandle( IReportItemModel.TOC_PROP ) );
	}
	/**