"Literal IDs" are error prone and most of the time unnecessary. Getting rid of them makes the source code shorter and easier to maintain. Standard IDs of `wx` should be used if possible. Then there is no need to give the text of buttons and menu items, and on some platforms appropriate icons will be shown automatically. And the IDs `wx.ID_OK` and `wx.ID_CANCEL` have special meaning in `wx.Dialog`\s.
First patch is for `drFileDialogPrefs.py`.