[gtk] (14 commits) Non-fast-forward update to branch image-loading

[Matthias Clasen <matthiasc src gnome org>]

The branch 'image-loading' 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:

  5baf805... Add code to load and save pngs
  d5ad248... Load pngs without gdk-pixbuf
  0625029... Save pngs without gdk-pixbuf
  f882e0a... Add tests for the png loader
  24b42ff... Add code to load and save tiff files
  fd01ce6... Load tiffs without gdk-pixbuf
  5836309... Add tests for the tiff loader
  4a982d0... Add gdk_texture_save_to_tiff
  c200227... Use our png loader for content (de)serialization
  df376ca... Use our tiff loader for content (de)serialization
  4fffa68... Add contentserializer tests for textures
  3abb7e1... Add code to load jpegs
  e20106a... Load jpegs without gdk-pixbuf
  13f4e50... Add tests for the jpeg loader

Commits added to the branch:

  3902fc7... Add code to load and save pngs
  55138cd... Load pngs without gdk-pixbuf
  4fb7b27... Save pngs without gdk-pixbuf
  cd26a6d... Add tests for the png loader
  61ca6b1... Add code to load and save tiff files
  f633ffa... Load tiffs without gdk-pixbuf
  5ccf01f... Add tests for the tiff loader
  6f7219b... Add gdk_texture_save_to_tiff
  8c770b3... Use our png loader for content (de)serialization
  39db15a... Use our tiff loader for content (de)serialization
  ef803bd... Add contentserializer tests for textures
  ee0a51f... Add code to load jpegs
  8613845... Load jpegs without gdk-pixbuf
  5a1e13b... Add tests for the jpeg loader