[gtk] (7 commits) ...Merge branch 'clipboard-test' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  be42644... Add more clipboard tests (*)
  e1a0e4b... Make clipboard tests run installed (*)
  6482954... Fix the clipboard test under X11 (*)
  f72ca06... Run gdk tests with an unset D-Bus address (*)
  5636384... Skip clipboard tests when they don't work (*)
  c1b6147... Install the clipboard-client binary (*)
  d69ac10... Merge branch 'clipboard-test' into 'master'

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