[l10n] Add Catalan translation
[l10n] Added Catalan (Valencian) translation
Keep user's last known location cached

This will make it faster to go to user's location on startup and ensure
we always go to some sane default if network or IP geocoding server is not
available.
Remove unused CPPFLAGS
Add a initActions utility

Add an utility function to declare GActions (borrowed from
gnome-weather)
Make "about" a window action

Declare the "about" as a window action instead of an application action
and the manually delegate to the window in order to show the about
dialog with the proper parent.