ENH: Update msgpack files if new data is available.
ENH: Improves handling of edge case in data update.

If the trading_days end date is not greater than the date being
tested, (this can happen if the algorithm's end date is set to a date
that is before the latest date available saved in the msgpacks),
then trying to get the location will fail, instead searchsorted
will get the lastest date available in the trading day map to use
as a test date.