Port run_pep8_test to Python to make it cross-platform

run_pep8_test right now only runs on Linux. These steps are done:
- port it to python
- update pep8.py from PyPi
- the command should be run as: python pep8.py --show-source --repeat
- make sure it doesn't show different results on Windows because of line endings
- let it report the files which are not yet converted to PEP8, if possible with percentage

I have updated to the latest pep8.py from PyPi and now much more pep8 bugs are reported in trunk. I have been fixing a big part already, but there is still a lot of work to do. Feel free to help to get the trunk clean again.