Keep logging config at a bare minimum (NullHandler)
Keep logging config at a bare minimum (NullHandler)

Let the user decide what logging they want to configure.

Explanation of this approach:
- https://docs.python.org/3/howto/logging.html#configuring-logging-for-a-library
- https://docs.python-guide.org/writing/logging/#logging-in-a-library

In client.py, __name__ will be pypushover.client.

NullHandler is basically a "no-op" that just ensures a handler is present.

KronosKoderS/py_pushover,KronosKoderS/pypushover