Waiting-list numbers on a scheduled class could stay at their old value for a while, so a class sometimes looked like it had nobody waiting when it did.
- Joining a waiting list while booking now updates the class right away.
- Cancelling a waiting-list place, or letting it time out because the booking was not completed, now frees the space in the displayed count immediately.
- When a waiting-list place turns into a confirmed booking after payment, the class numbers are refreshed at once.
- Waiting-list places created before this fix correct themselves the next time they are paid for.
