Should use Enum34 package and add to Travis Build

enum34 is a backport of Python 3.4 for earlier versions of Python.
https://pypi.python.org/pypi/enum34
Should use standard library backport instead of flufl.enum as want to be standard library anyway.
Easily installed with pip-3.2 and python3-pip already in Travis dependencies.
Package would need to be added to Travis config.