Update to latest gunicorn. Fixes #20
Update gunicorn configuration to use the sync worker by default. Updates the configuration to set the workers to num cpus * 2 + 1 as recommended. Uses gunicorn from bin rather than the management command as currently recommended. Fixes #24
Gunicorn no longer needs to be in the installed apps. No longer need gevent/greenlet in the production requirements since we are using the sync worker.
Merge pull request #35 from caktus/gunicorn-changes

Gunicorn Changes. Fixes #24 and fixes #20.