* Add swagger_ui_config option to configure the Swagger UI
There was no possibility to configure the Swagger UI. Through
this new option a config object can be passed to the UI via
a `swagger-ui-config.json` file.
* Add tests for swagger_ui_config option
removed test_decorators and test_parameter (this test is useless now);
removed the request/response containers and add new request response classes;
created a abstract api class and a api flask class;
derived classes will implements the get_response/get_request methods that will convert framework req/resp types to connexion req/resp types;
moved the jsonifier from produces to flask api;
created a abstract app class and a app flask class;
changed all validators to use the ConnexionRequest instead flask request;
changed the problem function to generate a ConnexionRequest;
created a new user variables container called context (this is a property of ConnexionRequest). this will be passed as kwargs to all operations functions;
this context is used on authentication;
fixed all tests to new API;
some changes that I did may not be documented in this commit.
