URGENT

TO BE DONE

WOULD LIKE TO HAVE
- Attacks are not kept centered well.
- Ideally we somehow color the correct/incorrect tags in the editor.
- Line numbering is needed for the editor window otherwise you cannot
  interpret attacks. Probably use wx.Py editor things.
- Preferences window.
  - Save in local file on close.
  - Scyther executable should be able to be set by means of preferences.
    (Using a file select dialog)
- Refactoring: constructing the comment of a claim (now in
  Gui/Scytherthread) should really be in Scyther/Claim.
