Update setup.py

PyPi deprecated several of their mirrors on Feb 15th.  The installation of tendenci will fail if this link is unavailable.

https://pypi.python.org/mirrors
remove mirrors from dependency_links and delete the blank dependency_links

The --use-mirror option has been deprecated in the latest pip
version bump
#792: Renamed Contact section to Author
Merge branch 'master' into bixly-testing