[scribus] Drop Shadow

[William F. Maddock]

No soft shadow obliterates anything that it falls upon, but only
modifies its appearance, much like the shadow of the earth modifying the
appearance of the moon during a lunar eclipse. Therefore, the following
is true:

In order for Scribus to properly support soft shadows, it would have to
first natively support both transparency and various forms of gradients
(especially gradients that directly follow the shape of an object), and
be able to treat transparency as a variable element of those gradients.

I know that sounds daunting to say the least (it certainly does to me),
but if you're going to do it, you might as well do it right.