2.1.1: Fix PyPI / setup.py Installation
- Changed `py_modules` to `packages` in `setup.py` To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle). To use in CPython, `pip3 install adafruit-circuitpython-ht16k33`. Read the [docs](http://circuitpython.readthedocs.io/projects/ht16k33/en/latest/) for info on how to use it.