flake8: Put configuration into standardized place (#1974)
flake8: Put configuration into standardized place (#1974)

As I found described here:
http://flake8.pycqa.org/en/latest/user/configuration.html

My motivation for doing this was that I always get 100 warnings in vim
when I save my file.  As this follows the standardized way, I hope
anything can without effort ripe the benefits.

I tested the autolinting functionality I have in vim (syntastic?) as
well as running the -e flake8 using tox.
rayrrr/luigi,rayrrr/luigi,PeteW/luigi,adaitche/luigi,Tarrasch/luigi,dlstadther/luigi,adaitche/luigi,jamesmcm/luigi,foursquare/luigi,dstandish/luigi,Houzz/luigi,samuell/luigi,soxofaan/luigi,foursquare/luigi,spotify/luigi,Houzz/luigi,stroykova/luigi,stroykova/luigi,samuell/luigi,foursquare/luigi,riga/luigi,ehdr/luigi,jw0201/luigi,h3biomed/luigi,dstandish/luigi,riga/luigi,h3biomed/luigi,soxofaan/luigi,republic-analytics/luigi,rayrrr/luigi,PeteW/luigi,Magnetic/luigi,adaitche/luigi,jw0201/luigi,Houzz/luigi,h3biomed/luigi,foursquare/luigi,dstandish/luigi,jamesmcm/luigi,ehdr/luigi,ContextLogic/luigi,republic-analytics/luigi,ContextLogic/luigi,jw0201/luigi,republic-analytics/luigi,Magnetic/luigi,ContextLogic/luigi,stroykova/luigi,Tarrasch/luigi,edx/luigi,edx/luigi,dlstadther/luigi,rayrrr/luigi,adaitche/luigi,ehdr/luigi,Magnetic/luigi,dlstadther/luigi,jw0201/luigi,spotify/luigi,Houzz/luigi,edx/luigi,republic-analytics/luigi,soxofaan/luigi,jamesmcm/luigi,PeteW/luigi,jamesmcm/luigi,spotify/luigi,spotify/luigi,soxofaan/luigi,dlstadther/luigi,Magnetic/luigi,Tarrasch/luigi,riga/luigi,stroykova/luigi,ehdr/luigi,samuell/luigi,h3biomed/luigi,riga/luigi,samuell/luigi,Tarrasch/luigi,edx/luigi,ContextLogic/luigi,PeteW/luigi,dstandish/luigi