[gtk] (8 commits) Non-fast-forward update to branch gamma-shenanigans

[Matthias Clasen <matthiasc src gnome org>]

The branch 'gamma-shenanigans' 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:

  51a06f0... Use our png loader for content (de)serialization
  b3daa42... Add async tiff load/save code
  32cb2f3... Use our tiff loader for content (de)serialization
  290591f... Add a jpeg loader
  32fb555... Load jpegs without gdk-pixbuf
  17719d2... Add vecorized half-float conversion
  dafe186... Improve half-float memory conversions

Commits added to the branch:

  2ef4e42... Add vecorized half-float conversion
  504b48f... Improve half-float memory conversions
  f25578f... png: Handle all formats when saving
  e3a43e5... Use our png loader for content (de)serialization
  2031b66... Add async tiff load/save code
  48ba92e... Use our tiff loader for content (de)serialization
  c222973... Add a jpeg loader
  c59495f... Load jpegs without gdk-pixbuf