[gtk] (7 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:

  ef65611... memorytexture: Add a 16bpp format
  13e574e... gdk: Upload 16bit images without conversion
  0841795... Load pngs using libpng
  15cf326... Save pngs using libpng
  ea1243a... Fix up tests for 16 bit textures
  8acfe22... Support floating point textures
  5517b03... Add a 32bit float format as well
  0b70c7a... texture: Generalize download_16bit
  b00c1ba... Support loading and saving float textures
  2fdfcf4... Lossless loading and saving for float textures

Commits added to the branch:

  1c90cf2... Support 16bit textures
  7ff8404... Add private api to download textures
  068499f... Support loading and saving 16bit pngs
  9dc0cae... Support 16-bit floating point textures
  120b671... Support 32-bit floating point textures
  9791dbd... Add gdk_texture_save_to_file
  290dd42... Support loading and saving float textures