[gtk] (7 commits) Non-fast-forward update to branch wip/otte/memoryformat

[Benjamin Otte <otte src gnome org>]

The branch 'wip/otte/memoryformat' 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:

  50390bf... Add private memory formats used by libpng
  26b9a37... png: Refactor png saving
  7827a0a... gl: Fix downloading textures *again*
  50c402c... gl: Move texture uploading to the renderer
  c879931... gltexture: Determine format in current thread
  68e42b8... gl: Refactor texture uploading
  e287290... gl: Use gdk_memory_texture_new_from_texture()

Commits added to the branch:

  1023bbb... Add memory formats used by libpng
  ed718a1... png: Refactor png saving
  add2e72... gl: Fix downloading textures *again*
  fb68ab8... gl: Move texture uploading to the renderer
  4896b7f... gltexture: Determine format in current thread
  8eed569... gl: Refactor texture uploading
  2e59a1a... gl: Use gdk_memory_texture_new_from_texture()