fix setup, bump version

Reads the `__version__` and `__url__` variables without importing the package.
The import was causing a setup failure if `requests` was not already installed. 

Inspired by:
https://github.com/mitsuhiko/click/blob/master/setup.py#L9-L11

and

https://github.com/sigmavirus24/github3.py/blob/develop/setup.py#L34-L40