[HPT-153] Pages belonging to a paged object should form a single connected sequence

https://bugs.dlib.indiana.edu/browse/HPT-153

Tests seem to be working.  I'd appreciate comments on whether the tests are good and thorough.

app/script/purge-all.rb is a bonus:  a tool to empty a Fedora instance of non-system objects.  My test development created plenty of trash and I needed an automated cleanup.  Share and enjoy!