update setup.py version and download_url
update setup.py version and download_url

Reverted to using already defined version variable so
that it is not defined in two places. This earlier change
was an oversight.

Updated download_url to github v3 API url:

/:owner/:repo/:archive_format/:ref

Note for :ref, this scheme implies a future git tag
of vX.Y.Z for each released version X.Y.Z.

capybaralet/fuel,udibr/fuel,dribnet/fuel,dmitriy-serdyuk/fuel,dribnet/fuel,janchorowski/fuel,mila-udem/fuel,udibr/fuel,janchorowski/fuel,vdumoulin/fuel,dmitriy-serdyuk/fuel,capybaralet/fuel,aalmah/fuel,mila-udem/fuel,aalmah/fuel,vdumoulin/fuel