This is to test the several implementations of Debian version comparison
algorithms.

Run it via `make test`.

`run.py` generates a file containing all permutations of pairs of versions. The
different programs then check whether versions are greater than, equal or less
than one another and output >, = and <, respectively in order. It is then
checked whether the output of all implementations is the same.

Currently, this checks the libdpkg C implementation, libapt and dose3.

Additionally, the following parsers could be added:

 - libdpkg-perl
 - libben-ocaml (in lib/benl_base.ml and lib/benl_dpkg.c)

The following do not use their own parser:

 - python-debian uses python-apt
 - libghc-dpkg-dev uses libdpkg-dev
 - ruby-debian uses libapt-pkg-dev
 - dpkg-dev-el uses `dpkg --compare-versions`