Avoid relying on inspect to list functions.
Avoid relying on inspect to list functions.

This allow to run python3 -m cProfile ./pycodestyle.py …. Otherwise,
as cProfile looks to wrap every functions (in a way I did not studied
in depth), the inspection of test function found no function, and no
test were run while running under cProfile, meaning that:

$ time python3 ./pycodestyle.py coefficients-148K.py
[loads and loads of errors properly reported]
real 0m4.712s
user 0m4.684s
sys  0m0.024s

$ time python3 -m cProfile ./pycodestyle.py /home/mdk/Downloads/pystyle/stats/git-clones/PmagPy/PmagPy/coefficients-148K.py
[no error reported as no check were found by inspection]
real   0m0.447s
user   0m0.436s
sys    0m0.008s

With this patch:

$ time python3 -m cProfile ./pycodestyle.py /home/mdk/Downloads/pystyle/stats/git-clones/PmagPy/PmagPy/coefficients-148K.py
[loads and loads of errors properly reported]
real 0m4.889s
user 0m4.852s
sys  0m0.032s

PyCQA/pep8