Small patch for gtkmenuitem.

[jrb redhat com]

Hi,

I rewrote the gtkmenuitem geometry management to be a little more sane,
and let you do things like allow multiple sized pixmaps in the
toggle_area, random arbitrary widgets, etc.  The old system had the size
hardcoded in the class structure, which meant that you couldn't change
the size of the toggle w/o reinheritting.  This should make the
gtkpixmapmenuitem in GNOME-libs somewhat easier to write, too (also,
when/if gdk-pixbuf is moved into gtk+, we can add a pixbuf menu item).

Patch is available at:
http://people.redhat.com/jrb/files/gtkmenuitem-size-alloc.patch.gz

Thoughts and comments?
-Jonathan