Changes to digiKam doc [patch]

[Antoni Bella Pérez]

  Hi,

  I have done the revision of the Catalan doc translation until almost at the 
end of chapter 2 -- that end seems to be out of date.

  I do not have English at the level to write doc, but I attached a patch to 
solve some questions, and I have some notes to report.

  I upload it to git server?

  Regards
  Toni