[gnome-control-center] Non-fast-forward update to branch wip/jsparber/background

[Julian Sparber <jsparber src gnome org>]

The branch 'wip/jsparber/background' 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:

  5899f34... [feat] start implementing new background settings panel
  bf1d601... [feat] flowbox works and somework
  293de2e... [feat] add stylesheet and layout fix
  9f263c3... [minor] replaced cario stuff with simpler code using only p
  f2a0924... [backport] fix background preview code
  4e0d8a2... [feat] add new class for GListStore
  4fe9a03... [feat] working wallpaper gallery
  7160592... [minor] change margin around background preview to 16
  3ab3c5a... [refactor] clean some code
  62ff0af... [feat] add buttons on bottom of gallery, no code yet
  e4a5fb4... [fix] fixed place for the border on top of the gallery and 
  c99ee23... [feat] add handler for buttons
  34d34af... [refactor] clean up and fix build warnings
  2549473... [refactor] use a Widget to figure out scale factor instate 
  0474f7a... [merge] merged changes from master and [refactor] removed u
  aab238b... [feat] use GListstore to store wallpapers and bind it to gt
  4d6dd61... [minor] clear settings object in dispose
  7cc9eb7... [feat] resize preview when the window size is less then 500
  1babb7c... [minor] display small preview on default
  6279327... [minor] resize preview with window
  16bfb5e... [feat] add slideload icon to time changing wallpapers
  a24302b... [feat] use cached pixbuf if the preview size didn't change
  93387d0... [fix] add space around clock icon
  1baeb6e... [minor] change margins for preview
  91313a1... [minor] change preview margin to 16
  901e440... [feat] add revealer to slide text
  1be9068... [feat] tried to fill flow box
  4e5cb46... [feat] change size of preview when panel is heigher then 70
  3dd2b4e... [feat] resize thumbnail to fill space a row
  a759103... [minor] change tile size
  c4f5490... [fix] use same margin size everywhere around the flowbox
  8f611ac... [feat] add icon for with time changing wallpapers
  f3fc51f... [refactor] moved gallery item code to grid-item class
  b093d29... [feat] center gallery
  20206f7... [feat] add width space around gallery, set min itmes per li
  0f4ff5f... [fix] set max children for line to 5
  0b15e92... [refactor] remove test-chooser-dialog
  8f5c71c... Merge branch 'background-center' into background
  b249a23... [refactor] remove chooser dialog code
  239c9e1... [fix] add missing source to Makefile.am
  fa648a9... [feat] set wallpaper and lockscreen
  21dd5b6... [refactor] remove code for downloading pictures
  af8737d... [refactor] remove old classes
  e1e5bf1... [refactor] fix code style issues and remove commented code
  3132625... [fix] add widget cast
  dfe2637... [refactor] remove private struct of cc-background-store htt
  62a4fa4... [refactor] move stuff from CcBackgroundStore::constructed t
  1bde5cc... [refactor] make cc_background_grid_item_set_ref static and 
  00c6d24... [minor] change cc_background_grid_item_get_ref to cc_backgr
  6256384... [refactor] less exposure of the GListModel by using a wrapp
  dc2bc58... [refactor] CcBackgroundGridItem derives directly from GtkDr
  29a520c... [minor] the methode new of grid item returns its own obj ty
  d58b105... [minor] cache tumbnail for wallpaper gallery for redraw htt
  298e4b4... [refactor] changed variable names and some minor style chan
  07f96d6... [refactor] cache slideshow-emblem icon https://bugzilla.gno
  6473475... [ui] only show top border for gallery view https://bugzilla
  cea26e1... [minor] add comment: the way of setting the background shou
  9856a98... Merge branch 'master' into wip/jsparber/background https://
  80520af... [refactor] remove chooser gallery from meson.build (needs w
  17c5453... [build] remove chooser stuff form meson.build and add new f
  dc6bf12... [refactor] remove old files and images https://bugzilla.gno
  fa365ac... [minor] change the hide that the user can set wallpapers al
  4835a6e... background: fix merge mistakes created during rebase

Commits added to the branch: