It also demonstrate nicely need to manually re-invoke two-column
zoom which was first reported by vmonkey at
http://www.mobileread.com/forums/showpost.php?p=1992328&postcount=119
I'm not quite sure that I prefer manual interaction any more :-)
This file is created using Inkscape and pdftk, so it's free for
re-distribution as a test suite, possibly using something
like Perceptual Image Diff http://pdiff.sourceforge.net/
to automate it.
