Pep8

Just passed source code through autopep8 plus edited some places by hand. There is still a lot of unresolved inspections:
```
(blitzdb)orgkhnargh@mint:~/code/blitzdb > find ./blitzdb -name '*.py' -exec pep8 {} \; | wc -l
516
```
Especially there is a lot of too long lines (length > 79).
I could fix that since it is easy enough for me. Are you guys interested in this kind of help?
Seems I didn't beak anything. Pytest summary: ```113 passed, 2 skipped, 7 error in 9.16 seconds```. Same as at master branch.