[gtk] (4 commits) Non-fast-forward update to branch matthiasc/for-master

[Matthias Clasen <matthiasc src gnome org>]

The branch 'matthiasc/for-master' 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:

  7af75c3... node-editor: Document the node format
  fd5945c... node-editor: Add a gear menu
  8454662... node-editor: Cosmetics
  ed4e56a... node-editor: Add a help window
  325c5ce... fixup! node-editor: Document the node format

Commits added to the branch:

  4f7f157... node-editor: Document the node format
  8770584... node-editor: Add a gear menu
  2b6f243... node-editor: Cosmetics
  d4ff275... node-editor: Add a help window