Fix route stop actions (context menu), enable/disable filter UI buttons, cleanup

- Route stop actions are handled in a switch, but the break statements were missing
- The stop action to create a new filter missed a line to add the new filter to the filter list
- Add/rename buttons weren't disabled, if all filters were deleted
- Fixed the "No-Items-Text", to give users a hint again, that filters can be disabled to show more departures
- Cleanup: Remove old (commented) code