List of stuff to do:

- Improve folder support
  - Make search work with folder names
  - Make import scripts work with folders
  - Fix loading expanded folders inside collapsed folders
  - Allow dragging more than one folder at a time
- Improve icon
- Design a better layout for details pane
- Add database merge functionality
- Add better toolbar icons
- Implement sanity check after saving db temp file
- Fix compatibility with Python 3
