Add py-whistle 1.0.1

Whistle is a simple tool that allow your application components to communicate
with each other by dispatching events and listening to them.

Whistle is an Event Dispatcher library for the Python 3.5+ language. It's
largely inspired from Symfony's EventDispatcher component.

Using an event dispatcher is a great way to write loosely coupled extensible
code, having each part only communicate using light events.

WWW: https://python-whistle.github.io/
WWW: https://github.com/python-whistle/whistle