pep8 and pyflakes applied

I didn't do anything with line length yet.
You don't need to rebase or open a new PR. Just modify in your branch. Github will add them into this PR, when been merged there is only one commit log in trunk.

A line length limit is fine. Actually, I'm following a line length base on my screen (I always split VIM vertically, so it is half of my screen about 89 chars) in most case. 99 chars is fine.