The categories tables should be sortable

[scootermorris]

Currently, the categories tables aren't sortable. I tried to fix this before release, but it turns out to be very, very complicated, so I decided to release without it.

[scootermorris]

Just a clarification. The tables are sortable by rows, but not by columns. Ideally, I should be able to double-click in the first column of the row and sort the row by the cluster number.