This complements Eddy's patch #963120 (now committed)
by allowing iconized windows to accept the new
document. Iconized windows don't belong to any desktop,
so they are ignored while looking for an Untitled tab
to receive the new document.
There is no preference, since I believe this is the
natural thing to do.
This is only tested on Debian Sarge w/ Enlightenment,
so please try to find problems.
TODO: If the last non-Untitled tab is closed, the
window should iconify itself. This would require a pref