Python integration tests - flake8 fixes (part 2)

This PR makes `flake8` fixes in the other half the main integration tests, see gh-2338, the commits are on a file-by-file basis. I`OmeroPy/test/setup.cfg` has been modified and so these files should be automatically checked by Travis. The integration tests on Jenkins should still run and be unchanged barring standard intermittent fails.

Note that this PR essentially fixes for `flake8` and a few minor formatting issues. I have left chunks of commented-out code that could probably be removed and I have left several examples of code that should really be fixed to be better `pytest` code.