Add pep8 config, use pep8 in travis

also, fix E111-E113 errors:
E111 - indentation is not a multiple of four
E112 - expected an indented block
E113 - unexpected indentation

Seems smarter to install latest release from PyPi. What guarantees the HEAD of master on their repo is not broken? I don't think we need the bleeding edge on something like this.