[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:

  59e7dbe... Add code to load and save pngs
  feacd4d... Load pngs without gdk-pixbuf
  de653d6... Save pngs without gdk-pixbuf
  714e847... Add tests for the png loader
  48af29f... Add code to load and save tiff files
  7c63a4a... Load tiffs without gdk-pixbuf
  9ad5f3a... Add tests for the tiff loader
  4990a5c... Add gdk_texture_save_to_tiff
  275c2c3... Use our png loader for content (de)serialization
  026f777... Use our tiff loader for content (de)serialization
  7a0c7cd... Add contentserializer tests for textures
  dc498fc... Add code to load jpegs
  962cf0f... Load jpegs without gdk-pixbuf
  7ed91bb... Add tests for the jpeg loader

Commits added to the branch:

  91f0677... Add code to load and save pngs
  fe1272b... Load pngs without gdk-pixbuf
  500e188... Save pngs without gdk-pixbuf
  2455f10... Add tests for the png loader
  f507e82... Add code to load and save tiff files
  3524570... Load tiffs without gdk-pixbuf
  4ed2635... Add tests for the tiff loader
  862509e... Add gdk_texture_save_to_tiff
  3fe060d... Use our png loader for content (de)serialization
  6f11bdd... Use our tiff loader for content (de)serialization
  82d43b3... Add contentserializer tests for textures
  c26e982... Add code to load jpegs
  56d3d47... Load jpegs without gdk-pixbuf
  d1b0fe3... Add tests for the jpeg loader