Changed the way filtering in the Edit Things, Browse Action and Browse Effect...

Changed the way filtering in the Edit Things, Browse Action and Browse Effect windows work: items, which names start with filter text are now displayed first.
Cosmetic tweaks to the way thing bounding boxes are rendered in Things mode when "Fixed Things Scale" option is enabled (bounding boxes of highlighted/selected things are now more opaque than the ones of unselected things).
Changed, Preferences form: action selected in the actions list is now stays selected when applying the filtering (unless it's no longer valid).