Add a quick subsurface tests

Just to have some code that uses subsurfaces inside a widget
tree, and not like a 'pseudo-toplevel'.
Make subsurface test use a stack

Just to show that it works.
Update Danish translation of properties
Raleigh: Drop decoration-layout style property

This is not used anymore.
Updated Hebrew translation
Updated Russian translation
Updated Russian translation
Updated Danish translation
Updated German translation
Remove reference to GTK+ 2 in reference docs

The reference applies to both GTK+ 2 and GTK+ 3, so remove mention of
the version number from the reference docs.

https://bugzilla.gnome.org/show_bug.cgi?id=736927
Fix parse-sass.sh script

The script runs into this error here:
OptionParser::NeedlessArgument: needless argument: --sourcemap=none
Fix warning grammar
Updated Hungarian translation
gtkwindow: Make sure to update the shadow width, opaque region and border windows when realizing

Otherwise, they might not be properly set before the window is mapped.

For the opaque region and border window, it means that they won't get
set before the next size allocation, which tends to not be a bit deal.

For the shadow width, though, _GTK_FRAME_EXTENTS has a different meaning
when it's set before the window is mapped, so we need to make sure that
it's properly set when the window is mapped.
Updated Hungarian translation
Updated Hindi translation
Updated Danish translation
[l10n] Update Catalan translation
[l10n] Updated Catalan (Valencian) translation
inspector: Avoid a crash

We were forgetting to free the hash table, which then gave
us weak ref notifies at an unexpected time.

https://bugzilla.gnome.org/show_bug.cgi?id=737026