BigQuery

## wip.

### Docs: https://stephenplusplus.github.io/gcloud-node/#/docs/master/bigquery

Carrying on from #262. Just opening this so anyone interested can follow along.

I don't understand this parameter's comment. Will the results be streamed back if I don't provide a callback? Will it only start streaming once all the results are in, or will it stream results as they are fetched?