[gtk] (45 commits) ...Merge branch 'new-style-menu' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  0d59ece... model button: Small fixes (*)
  fc6010b... model button: Add a role for titles (*)
  30f6bea... model button: Drop centered, inverted properties (*)
  b4aac42... widget-factory: Add another popover menu example (*)
  eda31df... model button: Redo layout (*)
  fc3d3fb... model button: Show shortcuts (*)
  dd572ed... model button: Look up accels if needed (*)
  3313322... menu section box: Introduce more section variants (*)
  e080f35... menu section box: Add style classes for display hints (*)
  84243d0... widget-factory: Redo the new-style menu (*)
  06470c2... widget factory: Improve manual popover menu example (*)
  698e39b... popover menu: Fix style classes (*)
  0755491... widget factory: Add a context menu example (*)
  640c793... modelbutton: Sizing fixes (*)
  59ed4da... box layout: Handle native children (*)
  724f315... Stop exporting gtk_popover_bind_model (*)
  609f165... Rationalize popover menu apis (*)
  f91cc6c... Introduce a popover bar (*)
  4d191aa... widget factory: Redo the menubar with a model (*)
  d736778... popover: Respect alignment for positioning (*)
  c1791d0... widget: Ignore natives for picking (*)
  583c6a9... popover bar: towards menubar-like behavior (*)
  407ab93... gdk: Always deliver key events to toplevels (*)
  d48a8fd... widget factory: Add mnemonics in popovers (*)
  6f689ec... label: Fix mnemonic visibility handling (*)
  4ecaa75... popover bar: Break out items (*)
  3d56a89... widget-factory: Don't use Return as accel (*)
  0d800ac... popover bar: Add a model property (*)
  f1eb072... widget-factory: Move the popover bar to the ui file (*)
  f01e5d2... popover bar: Add arrow keynav (*)
  ae8373f... menu button: Use proper focus api (*)
  f82898f... model button: Make left/right switch submenus (*)
  18fd512... popover bar: Implement focus (*)
  abc9fef... popover menu: Implement focus (*)
  8452b9a... Expand focus tests (*)
  143ea34... popover bar: Don't grab focus away from open menus (*)
  6342287... popover menu: Disappear on focus out (*)
  bc4f744... main: Warn if GDK sends us bad focus events (*)
  d78b645... popoverbar: Use a box layout (*)
  d936967... Adwaita: Adapt to popover bar changes (*)
  65f71cd... popover bar: Add setters (*)
  17ec958... Rename GtkPopoverBar to GtkPopoverMenuBar (*)
  8e5985d... Typo fix (*)
  3c1163e... popovermenubar: Add docs (*)
  2248980... Merge branch 'new-style-menu' into 'master'

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