Deprecate GValueArray

The GValueArray type was added in a time, during the Jurassic era or so,
when GArray did not have a representable GType. The GValueArray API has
various issues as well:

  - it doesn't match the other GLib array types;
  - it is not reference counted;
  - the structure is fully exposed on the stack, so it cannot be
    extended to add reference counting;
  - it cannot be forcibly resized.

The nice thing is that now we have a GArray type that can replace in
full GValueArray, so we can deprecate the latter, and reduce the
complexity in GLib, application code, and bindings.

https://bugzilla.gnome.org/show_bug.cgi?id=667228

gobject/tests/valuearray.c

@@ -1,3 +1,4 @@
+#define GLIB_DISABLE_DEPRECATION_WARNINGS
 #include <glib-object.h>
 
 static gint