[Clipart] HASH bug: diagnosed (at least partly)

[Jonadab the Unsightly One]

Heh.  Solve one bug, introduce another.

As it turns out that the parameter to XML::Twig that causes it to
preserve the original prefixes (fixing the svg: prefix bug) also
slightly changes the data structure.  Just enough to require a change
in the calling code.  This is why we suddenly started getting a *lot*
of instances of the hash bug when we fixed that bug.

We were *occasionally* getting it before, and I suspect for a
different reason, which we'll probably still have to track down later,
but I think I have a good handle on the sudden increase now and should
be able to make a significant improvement in time for 0.15.

-- 
$;=sub{$/};@;=map{my($a,$b)=($_,$;);$;=sub{$a.$b->()}}
split//,"ten.thgirb\@badanoj$/ --";$\=$ ;-> ();print$/