Safrs

* Improved swagger examples and references
* Return result with bulk post
* relax requirements

* fix bug in py3.8 (78)
* fix bug with swagger (79)

* fix a bug in 2.10 where attributes having the same name as the class are not included
* add flask-admin as an extra_requirement

* caching & instance-level permission check
* accept attributes for clinet-generated ids (72)
* improved default filtering, by SergioSoldado
* pass flask_restful method_decorators from expose_object
* fix bug in include parameter handling, reported by Matt Leiter

* Remove a debug print from v2.9.2
* Some minor fixes

* Improved performance
* Fix pagination bugs (70, 71)