Merge branch 'gunicorn_cwd' into needle

* gunicorn_cwd:
  adding directory parameter to control gunicorn process cwd
  [COOK-2403] Cast symbol to string in templates
  doc environment parameter, celery sub-resource
  COOK-2337: default environment attrs to {}
  COOK-2337: using merge instead of merge!

Conflicts:
	providers/gunicorn.rb
	resources/gunicorn.rb