[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:

  3902fc7... Add code to load and save pngs
  e94910e... Load pngs without gdk-pixbuf
  2655346... Save pngs without gdk-pixbuf
  ab3e3d6... Add tests for the png loader
  8bd5faf... Add code to load and save tiff files
  47b18e1... Load tiffs without gdk-pixbuf
  a1c7152... Add tests for the tiff loader
  d080fb0... Add gdk_texture_save_to_tiff
  186279d... Use our png loader for content (de)serialization
  765aa05... Use our tiff loader for content (de)serialization
  1860b48... Add contentserializer tests for textures
  7e72404... Add code to load jpegs
  11400dd... Load jpegs without gdk-pixbuf
  ba6d1de... Add tests for the jpeg loader

Commits added to the branch:

  c472844... Add code to load and save pngs
  03c76ac... Load pngs without gdk-pixbuf
  c4f9e66... Save pngs without gdk-pixbuf
  7164f38... Add tests for the png loader
  0e4020d... Add code to load and save tiff files
  189bb02... Load tiffs without gdk-pixbuf
  cede3cd... Add tests for the tiff loader
  e1ee30c... Add gdk_texture_save_to_tiff
  f55faba... Use our png loader for content (de)serialization
  2b82d12... Use our tiff loader for content (de)serialization
  20583e6... Add contentserializer tests for textures
  6645c8d... Add code to load jpegs
  a9ca889... Load jpegs without gdk-pixbuf
  09547c9... Add tests for the jpeg loader