Enhance TTMSFMXListEditor functionality for both Text|Value editing

  1. Show both Text and Value item parts in editor, and allow separate editing of Text and Value contents.
    It would require to add extra 'Separator' symbol, and|or image && image name properties, as well as separate Text|Value decoration settings to item properties.
    Plus, specific 'CanEdit' events may be introduced, to allow|prohibit Text && Value editing conditionally.
  2. Also, it may be feasible to derive ListEditor from two-way scroll box, not just vertical one, as it is now, so long horizontal items may be viewed.
  3. As an alternative, or supplement to long horizontal items case, visible text truncation options may be added to item properties, allowing, for instance, at most n characters to be shown, postfixed with ellipsis.