[gtk] (12 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:

  c415e10... Save pngs without gdk-pixbuf
  e2195e1... Add tests for the png loader
  af5510d... Add code to load and save tiff files
  c779b6c... Load tiffs without gdk-pixbuf
  f48a4fc... Add tests for the tiff loader
  0f7edd8... Add gdk_texture_save_to_tiff
  01b0f47... Use our png loader for content (de)serialization
  c558425... Use our tiff loader for content (de)serialization
  aa1ab78... Add contentserializer tests for textures
  13828ba... Add code to load jpegs
  6ab3501... Load jpegs without gdk-pixbuf
  09c5730... Add tests for the jpeg loader

Commits added to the branch:

  2655346... Save pngs without gdk-pixbuf
  ab3e3d6... Add tests for the png loader
  6a7370c... Add code to load and save tiff files
  9b3f842... Load tiffs without gdk-pixbuf
  20109c3... Add tests for the tiff loader
  0fb66c0... Add gdk_texture_save_to_tiff
  6a70aa8... Use our png loader for content (de)serialization
  ac52d85... Use our tiff loader for content (de)serialization
  b09532d... Add contentserializer tests for textures
  e4450db... Add code to load jpegs
  20d9cd5... Load jpegs without gdk-pixbuf
  f384d8c... Add tests for the jpeg loader