[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:

  b83ec2f... Add memory formats used by libpng
  cc283f9... png: Refactor png saving
  bcdcfc2... gl: Fix downloading textures *again*
  9985f2a... gl: Move texture uploading to the renderer
  17e6d0e... gltexture: Determine format in current thread
  b312952... gl: Refactor texture uploading
  5294a68... gl: Use gdk_memory_texture_new_from_texture()

Commits added to the branch:

  8821f09... Add memory formats used by libpng
  1a39be7... png: Refactor png saving
  37d9e89... gl: Fix downloading textures *again*
  a467095... gl: Move texture uploading to the renderer
  bd3045f... gltexture: Determine format in current thread
  b4e31c6... gl: Refactor texture uploading
  b91161b... gl: Use gdk_memory_texture_new_from_texture()