[gnome-control-center/wip/jsparber/background] (40 commits) ...background: fix merge mistakes created during rebase

[Julian Sparber <jsparber src gnome org>]

Summary of changes:

  4e43bd6... user-accounts: Prevent crashes if current user is not in ca (*)
  201f4f0... user-accounts: Prevent crashes if current user is not in ca
  1553a81... background: change margin around background preview to 16
  65476b1... background: add buttons on bottom of gallery without functi
  ca21c6c... background: fix border on top of the gallery and add ids fo
  0d89fa2... background: add handler for "Photo" and "Files" button
  e0ac4a8... background: clean up and fix build warnings
  430d70b... background: clear settings object in dispose
  5581502... background: resize preview when the window size is less the
  dbddcdc... background: add slide icon to time changing wallpapers
  8b2a9e6... background: add space around slide icon
  59c2bb6... background: change margins for preview to 16px
  de0df9b... background: change size of preview when panel is heigher th
  b5e4c38... background: resize thumbnail to fill space a row
  18ec8be... background: change gallery wallpaper size
  43e05a7... background: use same margin size everywhere around the flow
  73dc04c... background: add icon for with time changing wallpapers
  3a7393c... background: moved gallery item code to grid-item class
  db6210b... background: add white space around gallery, set min itmes p
  cac6304... background: set max children for line to 5
  52670fc... background: set wallpaper and lockscreen
  9acf346... background: fix code style issues and remove commented code
  bd42527... background: fix build warning by casting obj to gtkWidget
  81c9629... background: remove private struct of cc-background-store
  b057210... background: remove CcBackgroundStore constructer
  5ecc098... background: make cc_background_grid_item_set_ref static and
  c025c4a... background: change name cc_background_grid_item_get_ref
  9eb8204... background: less exposure of the the wallpaper store
  c3f7cb4... background: change base obj of CcBackgroundGridItem
  df9a7c6... background: CcBackgroundGridItem::new returns its own typ
  07f939e... background: cache tumbnail for wallpaper gallery for a redr
  5061523... background: changed variable names and small style changes
  ba02248... background: cache slideshow-emblem icon
  7340153... background: show only top border for gallery view
  2555616... background: add comment: the way of setting the background 
  0bf9e62... background: remove chooser gallery from meson.build (needs 
  5bebef6... background: adapt meson.build for file changes
  4645922... background: remove old source files and images form git
  4303fbe... background: change description for open in File and open in
  4835a6e... background: fix merge mistakes created during rebase

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