menubutton: set DROPDOWN_MENU hint on the menu toplevel

So the WM can render the menu shadows correctly, omitting the top side,
in the common case the menu is rendered down from a toolbar.

https://bugzilla.gnome.org/show_bug.cgi?id=679449
modelmenu: set the accel group on the GtkMenu

Or the accelerators added for actions in the menu won't be displayed in
the menu items.

https://bugzilla.gnome.org/show_bug.cgi?id=679166
application: fix double free of app_id

This is fallout from commit 257b42e2f9d0759cc79967034f80c571c600faf3 -
those fields were already getting freed in
gtk_application_shutdown_x11() and my commit caused crashes on quit
instead.

Thanks to Rico Tzschichholz for reporting the bug and testing this fix.
menu: notify attach-widget property when menu is detached

When the menu is detached, the attach-widget property changes value to
NULL, so we should notify a property change, like
gtk_menu_attach_to_widget() does.

https://bugzilla.gnome.org/show_bug.cgi?id=679454
modelmenu: listen for toplevel changes on the attach widget

Right now, when we create a GtkModelMenu for a GMenuModel, we listen to
changes to the menu's attach-widget to detect when a toplevel
GtkApplicationWindow becomes available to fetch actions from it.

This unfortunately breaks this simple code:

  GtkWidget *application_window = gtk_application_window_new();
  GtkWidget *menu_button = gtk_menu_button_new();
  GMenuModel *menu_model = get_menu_model();

  gtk_menu_button_set_menu_model(menu_button, menu_model);
  gtk_container_add(GTK_CONTAINER(application_window), menu_button);

Since GtkMenuButton creates a GtkModelMenu and sets itself as its attach
widget before it's added to a hierarchy containing a
GtkApplicationWindow.

Fix the bug by simply listening for changes in the window hierarchy, and
creating the menu model when the attach widget is added to an
application window.

https://bugzilla.gnome.org/show_bug.cgi?id=679454
entry: guard for != NULL before unreffing the pixbuf

In gtk_entry_get_icon_pixbuf() we unreference the pixbuf that
_gtk_icon_helper_ensure_pixbuf() gives us back, since the function
doesn't return a reference, and by doing so we're able to return the
reference owned by the cached icon helper.
Since the icon helper method can return NULL though, if no icon
properties have been set on it, guard for != NULL before unreffing the
pixbuf, as that would cause a critical warning.

https://bugzilla.gnome.org/show_bug.cgi?id=679537
a11y: Don't mess up if column gets hidden

We were using a function that insisted on visible columns for computing
the potential ID of an invisible column. Not good.

https://bugzilla.gnome.org/show_bug.cgi?id=675990
a11y: Add separate accessible for GtkLockButton

The accessible doesn't do anything yet, this is just infrastructure
work.
a11y: Get lockbutton text directly

Instead of letting the generic button code attempt to find the currently
displayed text, just return the text directly.

https://bugzilla.gnome.org/show_bug.cgi?id=677347
a11y: Make lockbutton notify about state changes

In particular, ensure that the name of the lockbutton gets updated as
the displayed text of the lockbutton changes.

https://bugzilla.gnome.org/show_bug.cgi?id=677347
OpenBSD: use G_N_ELEMENTS instead of nitems

nitems is never guaranteed to be defined in sys/params.h as it is meant
to be defined within a protected ifdef __KERNEL conditional.
Use G_N_ELEMENTS from GLib which is the proper way of doing this.
Add missing functions to the docs

://bugzilla.gnome.org/show_bug.cgi?id=678828
Silence the build

Hide gdbus-codegen behind $(AM_V_GEN) for silence and cleanliness.
Updated Norwegian nynorsk translation
GtkApplication: Fix unsetting menu models

Pointed out by Zachary Dovel in
http://bugzilla.gnome.org/show_bug.cgi?id=679705
level-bar: introduce GtkLevelBar

Similar to CcStrengthBar from gnome-control-center, but more generic and
with thorough CSS styling support.

https://bugzilla.gnome.org/show_bug.cgi?id=677892
visuals: add a visual demo for GtkLevelBar

https://bugzilla.gnome.org/show_bug.cgi?id=677892

https://bugzilla.gnome.org/show_bug.cgi?id=679409
docs: link against libgdk-3.la

https://bugzilla.gnome.org/show_bug.cgi?id=679409
Revert "visuals: add a visual demo for GtkLevelBar"

This reverts commit ffdd7a5e185879006d405ffd69f68ff60f5fccfa.

Pushed by mistake.
Revert "level-bar: introduce GtkLevelBar"

This reverts commit 126a2308ca467744178d4be3309403f6899de987.

Pushed by mistake.