Drop subunit and dependencies.

[tseaver]

zope.testrunner is dropping the feature, so we don't need to test with it.

[hannosch]

The Python 2.7 / PyPy 2 tests fail, as they still try to install python-subunit and there are no version pins anymore.

I think this needs to wait until there's a zope.testrunner release without subunit. And than this PR can both drop the version pins and update to the new zope.testrunner version in one go.

[tseaver]

@hannosch I've updated the various pins such that bin/test-ztk now passes for me on Linux with Python 2.7. Fingers crossed.

[hannosch]

setuptools is pinned in travis.yml to 28.0 same as it was in the versions file. I think you need to update both places to 33.1.1

[tseaver]

setuptools is pinned in travis.yml to 28.0 same as it was in the versions file. I think you need to update both places to 33.1.1

D'oh! Of course. tox-travis would help here, maybe?