added python 3.3 compatibility with absolute python_interpreter

I switched from Python 2.7 to Python 3.3 on windows with a virtualenv, and for me Flake8Lint stopped working when using a absolute path to python.exe

I believe I fixed the errors without breaking python 2.7 compatibility, although I didn't test it.

update consists of a import of the new print function and i also fixed a bug when you have disabled complexity...

lint.py only prints to console if you give a --complexity, even if it is disabled (-1) otherwise you recieve an error

i also made the descprition more clear...