[gtk] (4 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:

  4a4e822... Support 16-bit floating point textures
  169097f... Support 32-bit floating point textures
  e0807e1... Add gdk_texture_save_to_file
  8a7ee2e... Support loading and saving float textures

Commits added to the branch:

  73cafa1... Support 16-bit floating point textures
  fff033e... Support 32-bit floating point textures
  f94a95a... Add gdk_texture_save_to_file
  93ed4d4... Support loading and saving float textures