Auke Kok 06c900120e Add category series.
These can be accessed using enter teleporters where is_series==2.

At that point, the `box` meta value determines the category, not
the box id. Then the next box that is unplayed in that category
is offered for play.

For now, the player is sent a message if there are no more
unplayed boxes in a category.
2019-01-18 15:50:53 -08:00
..
2019-01-18 15:50:53 -08:00