text: Title: Swagger UI assumes body payload when using api_ns.expect(model) for HTTP GET handler
  Body: Looking through the the [docs](http://flask-restplus.readthedocs.io/en/stable/swagger.html), there's an example of setting a model as an expected input to the get request handler, and to me it would be reasonable to assume that restplus would use this model to validate query string parameters as it's the only place that would make sense for it to be in the request. When using the same model for a post, swagger UI renders it as body request parameter, which makes sense. I'm just wondering if I'm wrong in my assumptions and this is by design, or it's a bug?
  
  Current version of flask-restplus: 0.11.0
  
  ```python
  class SomeResource(Resource):
      
      @my_api_ns.expect(my_super_cool_model)
      def get(self):
          # This will render as a body request param, not expected
          return {}
  
      @my_api_ns.expect(my_super_cool_model)
      def post(self):
          # This will render as a body request param, as expected
          return {}
  ```