So far we've been getting away with only unit testing through Python.
However, there's plenty of (existing and upcoming) internal code that
would be nice to unit test directly in C. For a framework, I opted for
check (https://libcheck.github.io/check/) because it is minimal, mature,
and available on all major distros. Add the autotools scaffolding,
including a copy of the checkmk script from check 0.15.2 since RHEL and
CentOS don't package it. We check the dependencies at configure time but
only fail if they're not available at `make check` time. Also wire up
`setup.py test` to run `make check`.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
