Actionable dating notices, ordered by urgency

Computed from the same rows and rules as the dating list. One notice per person, only when it is the user's turn: she_asked (she left a question unanswered), cooling (still for 2 days or more) or your_turn. Ordered by kind, then by days parked. days is null when the real time of the last message is unknown. Used by the Alerts screen of the FlirtMaster edition.