[atomix/wip/gtk3-port] (29 commits) ...Merge branch 'wip/gtk3-port'

[Robert Roth <robertroth src gnome org>]

Summary of changes:

  9f52556... Updated Occitan translation (*)
  cb95d2d... Updated Russian translation (*)
  9121555... Updated Turkish translation (*)
  5e15f4f... Updated Portuguese translation (*)
  45c6770... Prepare release 3.17.90 (*)
  fd82c9d... use gtk_show_about_dialog to ensure close button is shown ( (*)
  54a77c1... Updated Portuguese translation (*)
  f90739f... Updated Spanish translation (*)
  a276dc1... Updated Hebrew translation (*)
  e1966a1... Updated Greek translation (*)
  1029be7... URL shouldn't be translatable (*)
  bcf1c50... Prepare release 3.17.91 (*)
  3460563... Updated Polish translation (*)
  bcae013... Prepared release 3.17.92 (*)
  13a4111... Prepared release 3.18.0 (*)
  a73c6c2... GenericName for atomix.desktop (*)
  225b953... Updated Slovak translation (*)
  d8654c6... Updated Finnish translation (*)
  3b3285d... Added gameplay tips (bgo#587868) (*)
  aac02fd... Add a semi-transparent background for better readability (*)
  7da9fa8... Prepared release 3.19.2 (*)
  7bc692b... Updated Czech translation (*)
  2646f50... Updated Czech translation (*)
  326432d... Updated German translation (cherry picked from commit 2ff60 (*)
  8970ba3... Updated Polish translation (*)
  8fb635f... Updated Spanish translation (*)
  56bc7d2... Updated Portuguese translation (*)
  f0890f6... Prepared release 3.19.3 (*)
  4a822e3... Merge branch 'wip/gtk3-port' (*)

(*) This commit already existed in another branch; no separate mail sent