Fixes #108.

Adds 2 extra columns, country and region, to the activty_events and flow_events tables. We need to get those 2 columns added to the CSV before we can apply this change (hence WIP), because without them the import will fail. This also means that, once applied, the scripts won't be able to re-import old data from before the columns existed.

@jbuck, based on the discussion in #108 (comment), do you think stackdriver logging will happen soon enough for us to just add columns to the CSV that way, or do you think we'll need to update the Heka filter as an initial step? I suspect it's the latter, but worth asking.

And if we do need to update the Heka filter, do you know who we should ask to help us? I used to know how to do this, but I can't remember what was involved now, or even where to find the code.