WIP: porting the package out of the nose dependency

[mcepl]

I am a maintainer of Python packages in openSUSE, and I am on my crusade of eliminating nose1 from our distribution. When I look at its repository on https://github.com/nose-devs/nose, the last release 1.3.7 was on 2 Jun 2015, and even the last commit on the master branch was on 4 Mar 2016. Moreover, there are some reports that nose1 will stop work with Python 3.9/3.10 (not sure which one).

This patch eliminates dependency on nose, which has been unnecessary for a long time. There are no additional dependencies (uses only unittest).

Unfortunately, the test suite fails for me. I am not sure what’s wrong, but 23 tests fail. See this complete build log for details.