gattrib: Divert to third party spreadsheet

[KaiMartin]

Let gattrib export and import a comma separated file
and call a regular spreadsheet application like
gnumeric on that file. This will immediately solve the
usability issues like search&replace, column width or
select multiple lines. No need to reinvent the GUI
here. In fact, you could completely scrap the gattrib
GUI and use gnumeric a a kind of external GUI.

---<(kaimartin)>---