* Package python-cram.
   cram is required to run some of the tests.
   cram's source is at <https://bitbucket.org/brodie/cram>.
   It's also listed in the python package index.
* Add python-cram as build-dependency and remove override_dh_auto_test.
* Deal with architecture-dependent portions of the python module.
   There's a C shared library that is compiled as part of the setup.py
   build.
