Fixed Flake8 Violations and Fixed Build on Travis

This Pull-Request fixes the all flake8 violations except E501.
Violation "E501" is "line too long".
I think that the default line width of pep8 with 80 characters is not enough.
Therefore the violation E501 is ignored.

Travis offers the python version 2.7 on it's machines.
Since we are relying on system packages (rpm, python-rpm, python-svn and python-yaml) I do not see any way right now how we can build on python 2.6, 3.2, 3.3 or pypy on travis.
Right now I still have problems with a test on my machine (which is running python 2.6).
This makes me wonder if the tests have ever been executed by anybody on python 2.6 ...

Anyways please merge this pull-request: I linted the code and with travis we have a build machine for the open-source-community now.