[gtk] (10 commits) ...Merge branch 'gtk-demo-tweaks' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  11f971d... gtk-demo: Cosmetic improvements to clocks demo (*)
  180a5a1... gtk-demo: Cosmetic changes to the dropdown demo (*)
  15257e3... gtk-demo: Fix a leak (*)
  b251893... Drop pango version checks (*)
  e35c0e0... gtk-demo: Add overline to the markup demo (*)
  e942689... gtk-demo: Cosmetics (*)
  bb7500e... gtk-demo: Cosmetics (*)
  b9d7dab... gtk-demo: Improve display of image sources (*)
  a28c75f... gtk-demo: Expand the sidebar by default (*)
  6ff8f1b... Merge branch 'gtk-demo-tweaks' into 'master'

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