[gtk] (13 commits) ...Merge branch 'wip/matthiasc/gsk-hdr' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  48781cf... memorytexture: Split out GdkMemoryFormat handling (*)
  149395c... gl: Move memory <=> GL format mapping (*)
  afa004f... memoryformat: Add gdk_memory_format_prefers_high_depth() (*)
  dc6e831... gdk: hdr => high depth (*)
  3f4fb93... cairo: Use GdkTexture for converting from pixbuf (*)
  2e555db... testsuite: Fail more accurately (*)
  8950c0d... texture: Make format a property of GdkTexture (*)
  2a08641... gsk: Add high depth rendernode api (*)
  9174814... ngl: Allow specifying texture formats (*)
  985d2d2... ngl: Determine intermediate formats (*)
  8a24def... ngl: Update framebuffer format for each frame (*)
  6f17429... ngl: Make render_texture high depth aware (*)
  8d9c392... Merge branch 'wip/matthiasc/gsk-hdr' into 'master'

(*) This commit already existed in another branch; no separate mail sent