testsuite: Add a clipboard test

I'm not sure I like it yet because it deadlocked once and I haven't
figured out why that is.
label: Fix gcc warning
label: Initialize lines value to -1

Fixes defaultvalue test.
window: don't change bottom margin for automatic CSD

We'll use a style class to be able to give this a different appearance,
but for the time being we don't really need to give this such different
margin.

https://bugzilla.gnome.org/show_bug.cgi?id=706592
window: add a style class when we automatically create the titlebar

To distinguish it from custom titlebars added from applications.

https://bugzilla.gnome.org/show_bug.cgi?id=706592
Add an 'Always on Top' item to the csd window menu

We want to make the csd window menu as similar as possible to the
mutter window menu.

https://bugzilla.gnome.org/show_bug.cgi?id=706323
x11: Add EWMH workspace handling api

Add a few functions that give access to the EWMH workspace
properties.
Add workspace handling to the window menu

The reimplements the current mutter window menu for
workspace changes.

https://bugzilla.gnome.org/show_bug.cgi?id=706323
wayland: wl_data_device.enter provides a serial number, not a timestamp
wayland: Use current serial when setting selection, not _wl_time_now()

The wl_data_device.set_selection request expects a serial number.
wayland: Compare serial numbers correctly to avoid overflow problems

We have to look at the difference between two numbers, which will always
be well-defined and give the right result, even in case of integer overflow.
wayland: Only set wayland selection for GDK_SELECTION_CLIPBOARD

Wayland only has one selection, which corresponds to GDK_SELECTION_CLIPBOARD.
wayland: Set type for GtkSelectionData for incoming contents

This is set from the incoming property type under X11.  Under Wayland
it will always be what we requested, so we can just set it to the target.
Tajik translation updated
Updated Czech translation
Punjabi Translation updated by Aman
Punjabi Translation updated by Aman
GDK/GTK on Windows: Fix build

Due to the work on gdk_cursor_new_from_surface (commit b2113b73),
get_cursor_for_pixbuf() in GdkDisplayClass was converted to
get_cursor_for_surface(), which means the GDK Win32 backend needs to be
updated for the code to build and run on Windows, plus some function
prototypes and declarations/calls need to be updated as well.

https://bugzilla.gnome.org/show_bug.cgi?id=705980
gdk/win32/gdkdevice-virtual.c: Various fixes

...for the gdk_cursor_new_from_surface work (commit b2113b73) where the
types of some parameters were changed, and also to silence a critical
GDK_IS_DEVICE when a menu item is selected (courtesy of LE GARREC Vincent
from bug 696756).

https://bugzilla.gnome.org/show_bug.cgi?id=705980
Updated Brazilian Portuguese translation for Gtk+-UI