Use in client

Typically, when using httpreverse to e.g. make http requests using whatever http client you have, you might want to do this:

1. First run just the Jinja expansion first and parse the resulting YAML string
2. Next, apply the request/response templates for the operations you expect to be using (or maybe all of them). Keep a copy of the the result
3. Finally, for each HTTP request, just parametrize the API operation being used, marshal parameters and body and fire away!