Listory could miss some listens when the Spotify Api misbehaves.
Sometimes the listens added to the last-recently-played endpoint
are showing up are out-of-order.
Because of our optimization to only retrieve listens newer than
the lastRefreshTime we would skip retrieving those out-of-order listens.
By always retrieving the maximum 50 listens we can be reasonably
sure that we got all the listens.
We also had to improve the handling of duplicate listens, as we now
have a lot of them, curtesy of removing the lastRefreshTime
optimization.
