Fixes to setup.py

This project looks interesting so I thought I'd take it for a spin. Here are a couple fixes I had to do in order to install it.

Also, there was a conflict in the set of dependencies in requirements.txt that made it impossible to install. I had to file an issue with SAValidation and work around it for now.

https://bitbucket.org/blazelibs/sqlalchemy-validation/issue/6/allow-any-version-of-python-dateutil

Thanks!