[gtk] (6 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:

  5b1d861... Add private api to download textures
  2cdc20d... Support loading and saving 16bit pngs
  85c1da6... Support 16-bit floating point textures
  eaf350c... Support 32-bit floating point textures
  c3de06d... Add gdk_texture_save_to_file
  8d6ef14... Support loading and saving float textures

Commits added to the branch:

  3c24d59... Add private api to download textures
  6c3661d... Support loading and saving 16bit pngs
  1d8cbc2... Support 16-bit floating point textures
  3e81fd2... Support 32-bit floating point textures
  2205d84... Add gdk_texture_save_to_file
  47de1b0... Support loading and saving float textures