[gimp] (26 commits) Non-fast-forward update to branch wip/passthrough

[N/A <ell src gnome org>]

The branch 'wip/passthrough' 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:

  56249ed... ^^^ wip/passthrough ^^^
  7739e17... app: add pass-through layer mode
  dff05d9... app: add GimpDrawable::get_source_node() vfunc
  407c7a4... app: connect layer backdrop to source node's input
  50546fb... app: implement pass-through mode in GimpGroupLayer
  e6d5472... app: add gimp_projectable_{begin,end}_render()
  0fbf039... app: add GimpTileHandlerProjectable
  68d7f4f... app: use {begin,end}_render() and GimpTileHandlerProjectabl
  e6e3a2e... app: implement {begin,end}_render() for GimpGroupLayer
  5b39e1d... app: move bottom-layer special casing to GimpOperationLayer
  6c69efc... app: adapt gimp_image_merge_layers() to handle pass-through

Commits added to the branch:

  2944dbd... Update Polish translation (*)
  f37a28a... Update Chinese (Taiwan) translation (*)
  65d75f0... Update Chinese (Taiwan) translation (*)
  98fb972... Update Chinese (Taiwan) translation (*)
  cd25f1d... Update Chinese (Taiwan) translation (*)
  b349f1a... Update Chinese (Taiwan) translation (*)
  e0dcf53... Bug 781804 - Dodge/Burn tool produces artifacts with negati (*)
  74606d0... app: improve GimpTool::button_release(GIMP_BUTTON_RELEASE_C (*)
  573d6b8... app: change the blend tool graph only if the enpoints were  (*)
  95b27a1... app: add tool-internal undo to the blend tool (*)
  e546b1a... Update Polish translation (*)
  3bb1f09... Bug 780698 - 32-bit integer FITS files won't open (*)
  530b62a... app: s/imagemap/drawablefilter/ in some comments (*)
  032f911... app: add parser/evaluator for the GUM language (*)
  af4eec1... app: add ui_meta keys for controlling some ui properties dy (*)
  328d9c4... ^^^ wip/passthrough ^^^
  3d1dcaf... app: add pass-through layer mode
  9bdd974... app: add GimpDrawable::get_source_node() vfunc
  6f301f4... app: connect layer backdrop to source node's input
  d400252... app: implement pass-through mode in GimpGroupLayer
  a93f130... app: add gimp_projectable_{begin,end}_render()
  a2b4c63... app: add GimpTileHandlerProjectable
  ee0d252... app: use {begin,end}_render() and GimpTileHandlerProjectabl
  5756e08... app: implement {begin,end}_render() for GimpGroupLayer
  a98a52b... app: move bottom-layer special casing to GimpOperationLayer
  0c36932... app: adapt gimp_image_merge_layers() to handle pass-through

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