Have curation replace the concept of "best"

[eteq]

A note here to remember based on discussion from the DSII jamboree: we probably don't want the concept of the "best" measurement to be baked into the database long-term. Instead the concept of "curated" datasets should replace that - i.e., the result of #6 . So then the user access the data by doing something like db.query_table('mcconnachie12_curation') or maybe db.query_table(curation='mcconnachie12') or similar.