[gtk] (53 commits) ...Merge branch 'kill-tree-menu' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  0b6e521... popovermenu: Use a weak ref for active item (*)
  fd0f01b... popovermenubar: Cosmetics (*)
  6f80eee... window: Complete the popover conversion (*)
  6255dcd... filechooserbutton: Be smarter about 'None' (*)
  22f6787... mountoperation: Use a popover (*)
  94e238c... placesview: Use a popover (*)
  f5e79b9... appchooserwidget: Remove ::populate-popup (*)
  b23fbe1... notebook: Remove menu remnants (*)
  0cf1e1e... applicationwindow: Stop using a menu bar (*)
  3d4acf6... window: Move F10 handling to popover menubars (*)
  62e9ea4... widget-factory: Remove the menubar (*)
  80e903a... docs: Stop taking menubar screenshots (*)
  360239a... docs: Remove menubars from the visual index (*)
  8b30661... docs: Avoid using a menu for an example (*)
  5d82142... accellabel: Remove an example using menus (*)
  4b4cf36... gtk-demo: Replace a menu with a popover (*)
  928f7fa... gtk-demo: Use a popover in the clipboard demo (*)
  8efa612... gtk-demo: Remove a somewhat silly bit of code (*)
  5c086b9... gtk-demo: Convert the dnd demo to a popover (*)
  5d2113f... gtk-demo: Remove the menus demo (*)
  abcd83d... gtk-demo: Cosmetics (*)
  6b691bc... gtk-demo: Remove menus from listbox demo (*)
  5ec9b15... gtk-demo: Convert the builder demo to a menu model (*)
  ca87048... gtk-demo: Remove the change display demo (*)
  e424246... combobox: Replace GtkTreeMenu with a popover (*)
  57b7e87... testsuite: Update combobox tests (*)
  8ee44d2... toolbar: Simplify overflow implementation (*)
  2c5f4c5... menutoolbutton: Fix sensitivity handling (*)
  4c9b0d8... menutoolbutton: Stop supporting menus (*)
  901518e... headerbar: Stop using GtkMenuButton::use-popover (*)
  2754312... menubutton: Stop supporting menus (*)
  941f22c... testsuite: Cosmetic change (*)
  59aeae3... testsuite: Remove menu tests (*)
  bf4ec50... testsuite: Remove menu special-casing (*)
  5c97f09... tests: Stop using menus (*)
  9e15f3d... label: Remove menu support code (*)
  7e8393b... widget: Remove menu special-casing (*)
  b59521b... inspector: Remove menu special-casing (*)
  57a8617... buildertool: Drop menu properties (*)
  0854140... label: Stop referring to GtkMenuItem in the docs (*)
  a2aefa8... accellabel: Don't mention GtkMenuItem in the docs (*)
  54b2727... docs: Remove mentions of GtkMenuItem (*)
  53d9445... doc: Build fixes (*)
  7ee5779... gtk: Remove menu code (*)
  06860bb... accelcellrenderer: Fix editing (*)
  3dd6cc4... accelcellrenderer: Stop grabbing (*)
  0bb9fc6... Remove gdk_seat_grab (*)
  3fd427c... win32: Use a regular window for printing (*)
  9b165c8... treeview: Use a popover for search (*)
  b063312... docs: Rewrite popover menu docs (*)
  85bf4cf... docs: Mention the demise of menus in the migration guide (*)
  52e0eef... docs: Touch up menu button docs (*)
  e12a580... Merge branch 'kill-tree-menu' into 'master'

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