g_object_ref_sink and GUnowned

[Tim Janik <timj imendio com>]

as a result of the recent "GTK_FLOATING broken in 2.9?" discussion:
  http://mail.gnome.org/archives/gtk-devel-list/2005-December/msg00107.html
as well as the "ABI and API for g_object_ref_sink()" discussion:
  http://mail.gnome.org/archives/gtk-devel-list/2005-December/msg00174.html

i've now changed CVS accordingly, so:
- gtk+ <= 2.8 + glib <= 2.8
  GObject is initially non floating;
  GtkObject is initially floating as always
- gtk+ >= 2.8.10 + glib >= 2.10,
  GObject is initially non floating;
  GObject offers floating API:
    g_object_is_floating(), g_object_ref_sink(), g_object_force_floating()
  GUnowned derives from GObject, has intiially a floating ref_count.
  GtkObject derives from GUnowned, so is initially floating as always
    for GtkObjects, the floating flag is stored as GtkObject.flags&GTK_FLOATING
    so it stays binary compatible wrg to GTK_FLOATING flags pokage.
- gtk+ >= 2.10
  the GTK_FLOATING, GTK_OBJECT_SET/UNSET_FLAGS APIs are deprecated

---
ciaoTJ