Allow source to be a query, and report errors in %bigquery extract.
Allow source to be a query, and report errors in %bigquery extract.

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