compressed: decompress it, and continue on our merry way.

Make the test script compress its ad rspec, since it's probably fairly
safe to assume that any slice embedding service has this patch applied.

A mapping on a 1.7 MB ad rspec formerly took about two minutes to
complete.  With this change, it can be done in just over 4 seconds.
Something is making big XMLRPC parameters go really, really slowly.