annoyances--: do not place desktop icons under shelves.

annoyances--: do not place desktop icons under shelves.

The new trend these days seems to be "place a shelf on top of the
screen", in that case your desktop icons will get under that shelf and
looks annoying, people laugh at E users that use that :-D (fortunately
I'm the one that usually laugh...)

Fixed, but possible other places to be fixed as well. If one wants to
avoid the shelves, use the e_zone_useful_geometry_get().

e_zone now emits E_EVENT_ZONE_MOVE_RESIZE when the useful geometry
becomes dirty. Maybe it is worth to add a new signal, but I'm reusing
it until someone complains.

SVN revision: 49431