Add cell magics to list datasets and tables.
Add cell magics to list datasets and tables.

craigcitro/datalab,googledatalab/datalab,yebrahim/datalab,yebrahim/datalab,parthea/datalab,yebrahim/datalab,craigcitro/datalab,googledatalab/datalab,googledatalab/datalab,parthea/datalab,craigcitro/datalab,craigcitro/datalab,googledatalab/datalab,googledatalab/datalab,parthea/datalab,parthea/datalab,craigcitro/datalab,yebrahim/datalab,yebrahim/datalab,parthea/datalab,googledatalab/datalab,parthea/datalab