[gtk] (12 commits) ...Merge branch 'matthiasc/for-master' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  01df133... text: Avoid clash of preedit and placeholder (*)
  e60ea00... reftests: Fix the background-origin test (*)
  aec0a49... colorswatch: Remove a redundant include (*)
  78b427c... dragsource: Actually use the paintable (*)
  028bccc... gtk-demo: Use proper drag icons in the dnd demo (*)
  dff5986... main: Keep the target widget alive (*)
  965483e... gtk-demo: Reorganize the dnd demo (*)
  e54060b... gtk-demo: Fix entry position in dnd demo (*)
  d2f979f... gtk-demo: Improve drag icon handling in dnd example (*)
  7fac6b3... gtk-demo: Improve editing in the dnd demo (*)
  0f053d1... gtk-demo: Improve rotation in the dnd demo (*)
  962c4d6... Merge branch 'matthiasc/for-master' into 'master'

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