TrackChanges: Errors Dependencies

Todo:

Check if there are any dependenies of these errors:

• TRANSLATE-1476 TrackChanges: JS Error when replacing a character in certain cases
• TRANSLATE-1548 TrackChanges: nested DEL tags in the frontend

Result:

• The error in 1476 was due to handling of ranges during the editing a segment.
  The error in 1549 likely happened because the CleanUp-process was not started when leaving (+ saving) a segment by doubleclicking another segment.
  Neither the code nor the events are connected.
• Search and Replace does use the cleanup both in handleReplaceDelete() and in insertReplaceNode().