Allow catalogue to specify earliest/latest birth/death dates

[davidscotson]

The birth and death matching are really handy, but I’ve noticed a tendency to get bad matches for common names that might show up in e.g. list of 18th century poets and also modern sports people. It seems that if the dates don’t match fairly closely then it falls back to not caring about the date at all (just speculation, not looked at code). It feels like many catalogues will have a natural min and max for these values, which would help narrow down searches by date, even if the actual date is not known e.g. a catalog originally compiled in 1900 will not know about births or deaths after that and so we can exclude later births, and not penalize missing deaths beyond this point, a sport that was invented in 2010 and is mostly played by young people could safely exclude people born before 1900 (though this is a bit fuzzier). If the two catalogues don’t overlap in birth/death date then we can assume there are no matches between them without further effort.