Updated Spanish translation
Updated Greek translation
Update to latest libgd
build: bump version to 3.9.0
shellSearchProvider: use serialized GIcons

Since GIO now has built-in support to serialize and deserialize generic
GIcon implementations to a GVariant, we can remove our custom code that
did that.

Bump the GLib required version to current git master for the new API.
Use GtkStack, GtkRevealer and GtkHeaderBar

Many of the occurrences can be ported with a one-to-one rename from
their libgd equivalents.
There are more cases where we can use a GtkRevealer for faders instead
of Tweener, which will be handled in a separate commit.
Use GtkRevealer for faders instead of Tweener

Now that GtkRevealer supports it.
places: use GtkStackSwitcher and GtkHeaderBar for the places dialog
Revert "Use GtkRevealer for faders instead of Tweener"

This reverts commit de8b10a7bb1b9e1c633437588cfe51b79a66cfbe.
preview: flip navigation buttons icon names for RTL

Or we'll end up showing buttons pointing in the right direction, since
halign respects RTL already.
Also, set an uniform horizontal margin on the buttons, so they don't
appear at a different position when flipped in the other direction.

https://bugzilla.gnome.org/show_bug.cgi?id=698857
Updated Czech translation
Updated Malayalam Translation
preview: add prev/back navigation with Left and Right keys

https://bugzilla.gnome.org/show_bug.cgi?id=696836
preview: add tooltips on preview navbar buttons

https://bugzilla.gnome.org/show_bug.cgi?id=699121
Updated Slovenian translation
build: Require GTK+ 3.9.1

Current GTK+ master is needed to use the new GtkSearchEntry
rate-limiting feature.
Simplify search entry timeout

GtkSearchEntry now uses a 150 msecs timeout (the same as in gnome-shell)
which means that we don't need to rate-limit ourselves.

https://bugzilla.gnome.org/show_bug.cgi?id=700525
Updated Norwegian bokmål translation
documents: Remove unused code

https://bugzilla.gnome.org/show_bug.cgi?id=700712
searchbar: Don't mess with the text input by the user

https://bugzilla.gnome.org/show_bug.cgi?id=699620