[gtk/matthiasc/for-master] (40 commits) ...Create the trash monitor async

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  bfebc2b... icontheme: Remove gtk_icon_theme_get_default() (*)
  b713b9f... icontheme: Remove async APIs (*)
  bbbe39f... icontheme: Make text direction a lookup argument (*)
  10023b5... icontheme: Remove GTK_ICON_LOOKUP_USE_BUILTIN (*)
  4c3363b... icontheme: Remove NO_SVG and FORCE_SVG flags (*)
  48b9791... icontheme: Remove gtk_icon_theme_rescan_if_needed() (*)
  3bba52e... icontheme: Remove crayon APIs (*)
  7e8d821... Revert "Break out cairo color matrix recoloring to gdk_cair (*)
  4b96ba5... icontheme: Remove gtk_icon_get_base_size() and gtk_icon_get (*)
  544cd1a... icontheme: Clean up includes (*)
  f7a5dd7... icontheme: Remove contexts (*)
  571021c... icontheme: Pass fallbacks as optional argument to lookup_ic (*)
  138de60... icontheme: Remove GENERIC_FALLBACKS (*)
  c91be54... tooltip: Don't css-validate (*)
  410541f... Rename GtkIcon to GtkIconPaintable (*)
  cc22987... Merge branch 'wip/otte/icontheme' into 'master' (*)
  3cb150a... widget: Remove _gtk_widget_is_drawable() (*)
  a163571... widgetfocus: Remove unnecessary check (*)
  3bb8b56... treelistmodel: Small documentation tweaks (*)
  6640881... maplistmodel: Add an example to the docs (*)
  903af75... widget: Skip not-drawable widgets in snapshot_child (*)
  3f7e409... Merge branch 'wip/otte/for-master' into 'master' (*)
  ed742f1... testperf: Allow measuring start time (*)
  b7b2510... testperf: More flexible mark selection (*)
  85ad943... placessidebar: Change some initial property values (*)
  1e6171a... Read bookmarks async (*)
  ed6c0dc... Don't export color picker functions (*)
  005ea7a... entry: Avoid criticals in dispose (*)
  47c21a2... textview: Don't update action state in dispose (*)
  b1d5de7... notebook: Don't trigger criticals in dispose (*)
  955305a... treestore: Silence compiler warnings (*)
  9e6ae7a... gdk: Silence some compiler warnings (*)
  9a446f2... frameclock: cosmetics (*)
  1cb575a... icontheme: Remove some dead code (*)
  b996b85... Add a lib64 variant of gtk.supp (*)
  fac435b... widget: Fix a memory leak with class actions (*)
  25c25ba... icontheme: Fix various memory leaks (*)
  54f6515... emojichooser: Add profiler marks for loading (*)
  2c2d69a... filechooser: Create volume monitor in a thread
  a3ff337... Create the trash monitor async

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