Add type annotations and refactor some APIs

- Add role and optional argument for auth_required.
- Rename openapi._OpenAPIMixin to openapi.OpenAPI
- Rename module scaffold to utils
- Change scaffold.Scaffold to utils.method_route
- Change _AuthErrorMixin to function handle_auth_error
- Return None for current_user if not found
- Merge openapi module back to app
- Add mypy check in tox.ini
- Change flake-8 max-line-length to 100

apiflask/__init__.py

@@ -1,9 +1,15 @@
-from .app import APIFlask  # noqa: F401
-from .blueprint import APIBlueprint  # noqa: F401
-from .decorators import auth_required, input, output, doc  # noqa: F401
-from .errors import HTTPError, api_abort  # noqa: F401
-from .schemas import Schema  # noqa: F401
-from .fields import fields  # noqa: F401
-from .security import HTTPBasicAuth, HTTPTokenAuth  # noqa: F401
+# flake8: noqa
+from .app import APIFlask
+from .blueprint import APIBlueprint
+from .decorators import input
+from .decorators import output
+from .decorators import doc
+from .decorators import auth_required
+from .errors import api_abort
+from .errors import HTTPError
+from .schemas import Schema
+from . import fields
+from .security import HTTPBasicAuth
+from .security import HTTPTokenAuth
 
 __version__ = '0.3.0dev'