Make the random difference between two equivalent dates to be of the order of seconds and not days.

The current version randomizes too much and the talks are all over the place.

filters.py

@@ -28,7 +28,7 @@ def sort_cards(cards):
     # cards on the same date.
 
     dates = [
-        dp.parse(card["date"]) + datetime.timedelta(rand(0, 10000))
+        dp.parse(card["date"]) + datetime.timedelta(seconds=rand(0, 10000))
         for card in cards
     ]