* Install the new ui.TabFrame widget into the Settings and Doodad
Dropper windows to give them properly tabbed interfaces.
* Doodad Dropper's new tabs divide the list of doodads into categories
to make them easier to find.
* The officially defined categories so far are:
- Objects (Start/End Flags and Box)
- Doors (All locked doors and keys, Warp Doors, and Electric Door)
- Gizmos (All buttons, switches, state blocks/doors, Electric Door)
- Creatures (Blue/Red Azulian, Bird, Boy)
* The "All" tab of the Doodad Dropper will show every doodad regardless
of its category or whether it fit one of the official categories.
* How doodads are assigned categories is by a special "category" tag in
their metadata, e.g. "category=doors,gizmos" - multiple supported.
