Remove `time` pending and syncing logic.
Update `time` and `coins` to account for current session.
Add `Session.duration` for current session duration.
Add `Session.coins_earned` for current session coins.
New `study_time_since` database function from session history.
Add `Lion.timezone`.
Add `Lion.day_start`.
Add `Lion.studied_today`.
Made `Table.queries` an instance variable.
Renamed the session channel types.