[gtk] (11 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:

  2fdad12... memorytexture: Add a 16bpp format
  4273a2e... gdk: Upload 16bit images without conversion
  2cb5c98... Load pngs using libpng
  68e5c6e... Save pngs using libpng
  20c0881... Fix up tests for 16 bit textures
  9963643... Support floating point textures
  9d85119... Add a 32bit float format as well
  94ff25c... texture: Generalize download_16bit
  1664e83... Support loading and saving float textures

Commits added to the branch:

  db3858a... Update Chinese (China) translation (*)
  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

(*) This commit already existed in another branch; no separate mail sent