Imporve coding style according to PEP-8.

- Indentation (soft tab)
- Maximum 79 characters in one line
- One-line docstrings
- In 'hashfile', using `while buf:` instead of `while len(buf) > 0:`

Caution! Not fully tested!
update function name
Add environment description

Remove manager.pyc
"w" -> 'w'