fix flake8 warnings

Mostly folding lines and fiddling with missing / superfluous spaces.
On a couple occastion, adding an intermediate variable or removing an
unused one.
fix flake8 issues in __init__.py files
fix flake8 issues in missed __init__.py
Merge pull request #1 from gurneyalex/7.0-fix-flake8

fix flake8 warnings