because it confuses gtk-doc and breaks some links. Also change the
"Index of new symbols in GIMP 2.x" sections to be what seems to be the
modern standard (looked at the GLib and GTK+ docs), and update some
other stuff.
So it works with all GObject versions, until we determine how useful
it is generally, and what API it should get for possible
libgimpwidgets inclusion.
Swallow GtkHSV back into GIMP and call it GimpColorWheel. Keep it in
modules/ for the time being. Clean up and undeprecate it. Replace
set_metrics() API by set_ring_fraction() and make it follow the size
of its parent container, making its use straightforward. Kept it clean
of GIMP color types so it can be easily adapted by e.g. Inkscape.
