Aiohttp-jwt

* Minor fix for middleware initialization check inside decorators.

* Raise `UnAuthorized` instead of `Forbidden` [129](https://github.com/hzlmn/aiohttp-jwt/pull/129). Thanks [rockwelln](https://github.com/rockwelln)

* Added preflight (OPTIONS) request skip [139](https://github.com/hzlmn/aiohttp-jwt/pull/139). Thanks [ckkz-it](https://github.com/ckkz-it)

* Switched to new style aiohttp middleware [94](https://github.com/hzlmn/aiohttp-jwt/pull/94). Thanks [Ranc58](github.com/Ranc58)

* Added `issue` and `audience` claims support [80](https://github.com/hzlmn/aiohttp-jwt/pull/80) . Thanks [idegree](github.com/idegree)

* Added [`auth_scheme`](https://github.com/hzlmn/aiohttp-jwt/blob/master/aiohttp_jwt/middleware.pyL24) option to middleware, that allows customization of authorization header prefix [77](https://github.com/hzlmn/aiohttp-jwt/pull/77). By default value is `Bearer`. Thanks gbarbaten

* Added explicit exception when decorators are used without proper middleware initialization & minor cleaning [85](https://github.com/hzlmn/aiohttp-jwt/pull/85)

* Added support for [class based views](https://docs.aiohttp.org/en/stable/web_quickstart.htmlclass-based-views) in decorators [52](https://github.com/hzlmn/aiohttp-jwt/issues/52). Thanks [citijk](github.com/citijk) for the report!

* Cleanup a bit project structure