Blender3D

I couldn't find equivalents to the `url_for('.index')` syntax and the Blueprint `template_folder` keyword argument, so I added a few changes to [my fork](https://github.com/Blender3D/flask-classy) of Flask-Classy: - `FlaskView.url_for()`. Adds the view...

`type(s) is type` doesn't work for old-style classes, but `inspect.isclass()` handles both old-style and new-style classes.