Connexion 2.0 (#619)

- App and Api options must be provided through the "options" argument (``old_style_options`` have been removed).
- You must specify a form content-type in 'consumes' in order to consume form data.
- The `Operation` interface has been formalized in the `AbstractOperation` class.
- The `Operation` class has been renamed to `Swagger2Operation`.
- Array parameter deserialization now follows the Swagger 2.0 spec more closely.
  In situations when a query parameter is passed multiple times, and the collectionFormat is either csv or pipes, the right-most value will be used.
  For example, `?q=1,2,3&q=4,5,6` will result in `q = [4, 5, 6]`.
  The old behavior is available by setting the collectionFormat to `multi`, or by importing `decorators.uri_parsing.AlwaysMultiURIParser` and passing `parser_class=AlwaysMultiURIParser` to your Api.
- The spec validator library has changed from `swagger-spec-validator` to `openapi-spec-validator`.
- Errors that previously raised `SwaggerValidationError` now raise the `InvalidSpecification` exception.
  All spec validation errors should be wrapped with `InvalidSpecification`.
- Support for nullable/x-nullable, readOnly and writeOnly/x-writeOnly has been added to the standard json schema validator.
- Custom validators can now be specified on api level (instead of app level).
- Added support for basic authentication and apikey authentication
- If unsupported security requirements are defined or ``x-tokenInfoFunc``/``x-tokenInfoUrl`` is missing, connexion now denies requests instead of allowing access without security-check.
- Accessing ``connexion.request.user`` / ``flask.request.user`` is no longer supported, use ``connexion.context['user']`` instead

examples/helloworld/README.rst

@@ -1,11 +0,0 @@
-===================
-Hello World Example
-===================
-
-Running:
-
-.. code-block:: bash
-
-    $ ./hello.py
-
-Now open your browser and go to http://localhost:9090/v1.0/ui/ to see the Swagger UI.

examples/helloworld/hello.py

@@ -1,12 +0,0 @@
-#!/usr/bin/env python3
-
-import connexion
-
-
-def post_greeting(name: str) -> str:
-    return 'Hello {name}'.format(name=name)
-
-if __name__ == '__main__':
-    app = connexion.FlaskApp(__name__, port=9090, specification_dir='swagger/')
-    app.add_api('helloworld-api.yaml', arguments={'title': 'Hello World Example'})
-    app.run()

examples/helloworld/swagger/helloworld-api.yaml

@@ -1,29 +0,0 @@
-swagger: "2.0"
-
-info:
-  title: "{{title}}"
-  version: "1.0"
-
-basePath: /v1.0
-
-paths:
-  /greeting/{name}:
-    post:
-      summary: Generate greeting
-      description: Generates a greeting message.
-      operationId: hello.post_greeting
-      produces:
-        - text/plain;
-      responses:
-        200:
-          description: greeting response
-          schema:
-            type: string
-          examples:
-            "text/plain": "Hello John"
-      parameters:
-        - name: name
-          in: path
-          description: Name of the person to greet.
-          required: true
-          type: string