FreeBSD 10, Rails 4 and Capistrano 3

Thank you for this script! 
I had issues on newer versions of bsd, rails and capistrano, so I am just sending over my working changes, in case someone ever needs it. I don't expect you to merge it, as it will break your setup.

- Rack based rails app supported by default
- FreeBSD 10 support without set_rcvar in rc.conf
- Capistrano 3 directory structure support (shared/tmp/pids)
- Better naming of the unicorn config file (it's already in config dir, no need for .conf)