Bump to nginx 1.6.0 and use nginx-sticky-module-ng

* Use nginx 1.6.0 (ea2dabd84d0a2d0153071484195ecd683b87e9ef)
* Swap to nginx-sticky-module-ng (nginx-sticky-module is unmaintained)
Merge pull request #5 from reedloden/nginx-1.6.0

Bump to nginx 1.6.0 and use nginx-sticky-module-ng