[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:

  9972202... Add code to load and save pngs
  da828ec... Load pngs without gdk-pixbuf
  5f9ce4a... Save pngs without gdk-pixbuf
  789b7ca... Add tests for the png loader
  fe6a5e8... Add code to load and save tiff files
  0e0801a... Load tiffs without gdk-pixbuf
  88b12e7... Add tests for the tiff loader
  722914c... Add gdk_texture_save_to_file
  e79d8d5... Use our png loader for content (de)serialization
  b3dcdb4... Use our tiff loader for content (de)serialization
  ab0a34b... Add contentserializer tests for textures
  b2e6951... Add code to load jpegs
  abaf2f0... Load jpegs without gdk-pixbuf
  81171f6... Add tests for the jpeg loader

Commits added to the branch:

  ff3597e... Add code to load and save pngs
  06a9917... Load pngs without gdk-pixbuf
  4d04681... Save pngs without gdk-pixbuf
  f6ebbec... Add tests for the png loader
  9f6d7f4... Add code to load and save tiff files
  dcdad73... Load tiffs without gdk-pixbuf
  1520a04... Add tests for the tiff loader
  be6bd7f... Add gdk_texture_save_to_file
  9a9950e... Use our png loader for content (de)serialization
  4b546ef... Use our tiff loader for content (de)serialization
  3fef570... Add contentserializer tests for textures
  750149a... Add code to load jpegs
  e496984... Load jpegs without gdk-pixbuf
  d4dd8c1... Add tests for the jpeg loader