Ensuring flake8 is compatible with black.

[gabrieldemarmiesse]

See #932 for more context

Some modifications were added to ensure we don't get conflicts between black and flake8.

Actually pycodestyle have checks that are really nice to have even if we use black. It would be beneficial for us to keep them. e.g.:

• do not compare types, use ‘isinstance()’
• do not use variables named ‘l’, ‘O’, or ‘I’
• do not use bare except, specify exception instead
  and so on...

For this reason, I followed black's documentation and only changed a few rules to ensure compatibility.

[seanpmorgan]

LGTM Thanks @gabrieldemarmiesse !