[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:

  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

Commits added to the branch:

  5baf805... Add code to load and save pngs
  d5ad248... Load pngs without gdk-pixbuf
  0625029... Save pngs without gdk-pixbuf
  e45f359... Add tests for the png loader
  e9c99d3... Add code to load and save tiff files
  9ed4ee5... Load tiffs without gdk-pixbuf
  c358c0e... Add tests for the tiff loader
  345bd19... Add gdk_texture_save_to_tiff
  f1c0631... Use our png loader for content (de)serialization
  94e55c8... Use our tiff loader for content (de)serialization
  2c1e124... Add contentserializer tests for textures
  ea5fdfb... Add code to load jpegs
  6d36fea... Load jpegs without gdk-pixbuf
  76ae4ab... Add tests for the jpeg loader