Merge pull request #10 from yakky/master

Add badges
Optional middleware overriding
Python 3 support
Add documentation
Merge pull request #11 from yakky/feature/optional_middleware

Add flag to make middleware overriding optional
Merge pull request #13 from yakky/feature/py3

Python 3 support
Add requirements-tests. Add Makefile for common tasks.
Merge pull request #14 from yakky/cleanup

Add requirements-tests. Add Makefile for common tasks.
Python 3 as a first class citizen
Bump version