Fix missing return from quartz_filter_keypress

(cherry picked from commit 0ae728e2424406f1dab3878a31942d9dd8862c1a)
Fix anonymous assistants

GtkAssistant supports not showing the sidebar with the page
titles (if the page have no titles). Unfortunately, we were
hiding the sidebar in this case, but still rendering the frame
behind it, leading to a broken appearance.
cssimage: Add forgotten line

That line was already missing in the initial commit it seems.
GtkEntry: ellipsize placeholder text

The placeholder string is truncated when there's no
room for it in entry's width.

So, by ellipsizing it, the user can notice the text
was truncated so that they can workaround that by,
for example, maximizing the window.

https://bugzilla.gnome.org/show_bug.cgi?id=702763
Optimize gdk_x11_screen_supports_net_wm_hint()

Move the call to gdk_x11_atom_to_xatom_for_display() outside of the
search loop in gdk_x11_screen_supports_net_wm_hint().  In my test case
(running Audacious for about a minute), this reduced the total number of
hash table lookups performed from 370,000 to 230,000.

https://bugzilla.gnome.org/show_bug.cgi?id=702913
Add missing allow-none annotations
GdkDeviceManagerXI2: chain up in constructed

Dispose does chain up, and the parent class' dispose expects
that the object has been fully constructed.
GdkVisualX11: Add a dispose implementation

We need to be able to drop X resources before finalization.
GdkScreenX11: Dispose visuals

If we let them hold onto their X resources until finalize,
it is too late.
Avoid integer overflow

Use g_malloc_n in gdk_cairo_set_source_pixbuf when allocating
a large block of memory, to avoid integer overflow.

Pointed out by Bert Massop in
https://bugzilla.gnome.org/show_bug.cgi?id=703220
GtkApplication: Do not assert sm_proxy != NULL in inhibit functions

Applications have no way of finding out if a session manager proxy was
successfully created in gtk_application_startup_session_dbus(), so it's not
appropriate for certain public GtkApplication functions to be asserting the
presence of a session manager proxy as if it were a programmer error.

This affects:

   gtk_application_inhibit()
   gtk_application_is_inhibited()

If sm_proxy is NULL, the function should just return silently.

In the case of gtk_application_uninhibit(), the application should only be
calling this if it obtained a valid cookie, which implies the presence of a
session manager proxy.  I noted that with a comment.

https://bugzilla.gnome.org/show_bug.cgi?id=701365
GtkRange: disconnect signals in the accessible

We were only disconnecting the signal in finalize, when
the widget was already unset. Instead, override the widget_set
and widget_unset vfuncs of GtkAccessible, and keep a reference
to the adjustment.

https://bugzilla.gnome.org/show_bug.cgi?id=705692
GtkSpinButton: disconnect signals in the accessible

Just as for GtkRangeAccessible, we were not even trying to disconnect
the signal handler from the adjustment. The same fix works here:
override the widget_set and widget_unset vfuncs.

https://bugzilla.gnome.org/show_bug.cgi?id=705692
Make symbolic icons work with the current rsvg

The rsvg loader now restricts what external files it will
allow to load from an svg. Thus our xinclude trick doesn't work
anymore. To work around that, embed the payload in a  data: uri.
This is somewhat ugly, but the best we could come up with.
window: Some protection against nested set_focus() calls

Since set_focus() can triger events, have a check to make
sure state is still valid before firing is-focus signal.

https://bugzilla.gnome.org/show_bug.cgi?id=706152
Fix keyboard activation of menu buttons

Keyboard activation relies on the menu not being visible,
so ensure that it isn't when the menu is attached.

Problem tracked down by Vincent Le Garrec,
https://bugzilla.gnome.org/show_bug.cgi?id=688738
iconview: Respect the fixed item width when adjusting the wrap width

Restore the code the way it was in GTK2.

https://bugzilla.gnome.org/show_bug.cgi?id=680953
Fix make check
3.8.3
Bump version