schemas/vegbien.sql: location: Dropped unique constraint on lat/long because it covered only some rows, which interfered with column-based import's selection of different insert methods based on the presence or absence of duplicate keys. (With the constraint, locations with coordinates would have duplicates eliminated, but locations without coordinates would not be able to find which row was added for a particular location because there was no lookup key to join on, and would all just use the first inserted row.) The previous behavior didn't make much sense anyway, because it would assert that two locationevents occurred in the same place just because they had the same coordinates, which may not have been precise enough to make this determination. Asserting that two locationevents occurred in the same place is really part of the secondary validation, not the import process.