Merge branch 'diable-multiprocessing-on-win' into 'master'

Diable multiprocessing behaviour on Windows

*Description of changes*

Due to https://bugs.python.org/issue27649, while Flake8 can *run* with multiprocessing on Windows, it does not behave as we expect it to behave. To provide the best experience that is in agreement with our documentation, we must disable multiprocessing until https://bugs.python.org/issue27649 is fixed and released.

Closes #184

See merge request !105