Fix PEP8 coding style violations

`pep8 *.py --ignore=E501` gives no output anymore.

TODO: Fix long lines

As part of http://24pullrequests.com
Fixed PEP8 coding style violations of "unit"folder

`pep8 unit/*.py --ignore=E501` tells us everything is ok.

As part of http://24pullrequests.com
Merge pull request #3924 from habi/pep8ify

PEP8 : Fix PEP8 coding style violations in unit and helper scripts