Fixed bugs with Nginx and Unicorn.

Nginx configuration test failed due to missing proxy_headers so Skeleton has been updated to use a custom Nginx cookbook. Unicorn was having a hard time with restarts and zero-downtime deploys but those problems are fixed. Config and helper files have been cleaned up some more. Deploy setup is now stage independent although this commit comes with a staging capistrano environment. Production environments should not be used for testing. There's a staging RDS db connected to the app but migrations are not working just yet. The final step to getting Rubber-free deployment to MVP status is to get migrations working.