[gimp] (6 commits) Non-fast-forward update to branch wip/nielsdg/use-default-marshallers

[Niels De Graef <nielsdg src gnome org>]

The branch 'wip/nielsdg/use-default-marshallers' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  5854d49... Cleanup GObject signal marshallers

Commits added to the branch:

  9908c14... devel-docs: Fix id of PROP_BLEND_SPACE (*)
  7f3bb72... app: print gimp_versions.json parsing error on stderr. (*)
  a05b085... app: show time of last version update check. (*)
  75a03b0... app: let's display the release comment in update notificati (*)
  21e090a... app: display revision number in About dialog if > 0. (*)
  a013e7f... Cleanup GObject signal marshallers

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